"That's nothing more than a tremulous fluctuation," he opined, as Senator Nick Xenophon closed the graph directly contradicting the well-rehearsed argument the man was executing, extolling the virtues of the status quo.

It was 2009 and the "alco-pops" tax debate was raging on the hill, the man: a lobbyist for the alcohol industry.

But, like hundreds of others working the corridors of Parliament House, his name cannot be found on the official government register.

Xenophon, a veteran of the game, was not worried by the fact, as it was clear why he was there and who he represented.

But numerous political observers remain concerned about the increasingly opaque networks of professional influencers trying to reach the ears of the nation's legislators.

Influence peddlers, rent seekers and factional powerbrokers – as little as a third of those seeking to help shape government policies face the strictures of the code of conduct or the transparency of the register.

The anecdote, as Senator Xenophon presents it, illustrates the lighter side of the industry – a lobbyist determined to win the argument for his client irrespective of the facts.

It is an industry as old as democracy, the players of which usually prefer to employ subtle methods to influence political outcomes, not the blunt force of the party room or the headlines.

Australia never had a Jack Abramoff.

But the nation did have Brian Burke and a series of scandals of intrigue and influence that led to the creation of the current register in 2009.

Never intended to capture in-house government relations staff at big companies, unions, industry associations, non-government organisations or charities, the register has long been criticised for its restriction to third-party lobbyists.

While there are currently 540 individual lobbyists on the register across 239 firms, servicing more than 1600 clients, such figures vastly underestimate the scale of the influence industry.

Due to the wide exemptions, it covers at most a third of the total lobbying effort targeting the hill, Australian National University Professor John Warhurst argues.

"If (the purpose) is to give a broad picture of the amount of lobbying and who's lobbying on what and for whom, then it has to include a wider range of lobbyists," Professor Warhurst says.

"Otherwise you've got a lobbying register that only covers a third of all the lobbyists in the country."

In the absence of a more accurate public record, the best indicator may be the 1497 "sponsored passes" to Parliament House carparks that were on issue in May last year, passes largely used by lobbyists.

Passes which outnumber the individuals on the register almost three to one.

Back in 2009, Liberal senators Concetta Fierravanti-Wells and Mitch Fifield agreed with such calls, urging the Rudd government to extend the regulations to "embrace unions, industry associations and other businesses conducting their own lobbying activities".

It was a recommendation the government ignored, as "it is clear whose interests they represent" and no government since has acted on that call or the majority committee's urging for a wide-ranging review of the register and code of conduct.

The current government did not respond to Fairfax Media's questions.

Rather, it has been kept "under review", allowing for a series of minor changes to be made, as well as then-Prime Minister Tony Abbott's 2014 edict to de-register any lobbyists who also held positions in the executives of political parties.

Keeping a watching brief on the issue ensured no holistic review or inquiry into the industry, or the rules governing it, has been completed in the eight years since the register's inception.

Senator Xenophon told Fairfax Media that given the piecemeal approach over the years, it was time for a review, potentially as part of a wider inquiry into the way influence and money is exercised in Canberra.

"It is well overdue, but it needs to be done in a credible way, and I think it should be part of a broader review of the influence that industry, unions, all lobbyists and money has on politics in Australia," he said.

"But having any regulation needs to be effective regulation, rather than just make people feel good."

Despite the recent election handing him more power than ever, Senator Xenophon said it had not attracted more attention from the industry.

"Not much has changed since the election – if you're already at saturation level (of lobbyists), how many more are going to come your way?" he said.

While many regulated third party lobbyists who spoke to Fairfax Media back extending the regime, the peak body for many industry groups, the Australian Chamber of Commerce and Industry, remains opposed.

It is a position understood to be reflected by many others who are not captured, if submissions to a 2008 Senate inquiry are any guide.

Chief executive James Pearson said when politicians meet with chamber staff, "they know that we are speaking on behalf of our members" and the chamber "sees no need to alter the arrangements".

The chamber is one of many groups seeking to influence the nation's top legislators, many of which populate the offices of Manuka, Barton and Civic.

While the passes provide access to Parliament House, a permanent Canberra office is a stronger signal that a lobbyist – often travelling interstate – is "serious" about their business.

As one industry veteran put it: "Our business is in Canberra, but most of our clients aren't".

WPPAUNZ head of government relations companies, Justin Di Lollo, said that all successful firms "have a presence in Canberra".

"If they don't it means they're not serious about lobbying the federal government," he said.

But access – or "door-opening" – is just one part of the game.

Perhaps at the core, lobbyists are political tacticians, serving a client and maintaining their role, rather than a party, electorate and self-interest as some backbenchers might.

They represent an occupational hazard for Canberra's bureaucrats, but courtesy of the "revolving door", can equally represent a career opportunity.

Whether former minister, public servant or political adviser, there are about 190 on the register listed as ex-government representatives – the varying time limits on their transfer from one role to the next seem to be little barrier.

They use many methods – from creating a groundswell of public support that can be used to influence backbenchers and cabinet in turn; to advising clients on submissions to inquiries, reviews and "white papers" that sit at the nexus of corporate interest and a government's agenda – all the while shepherding a particular decision through the existing channels.

"The first thing is always that you've got to win the argument," one industry veteran says.

"Most people aren't going in with factional heavies and trying to lean on people, we get the client to organise their thoughts, say why their case for a decision is in the national interest and win the argument."

Similarly, Mr Di Lollo said much of the lobbyists work was in "massaging the message" and "understanding how small 'g' government works, as well as understanding how big "g" government works – or this particular government".

"Ministers simply don't have the power to influence a decision without the process behind it," he says.

"The reality is if you need a decision out of government, then the more you need to understand the process – very rarely is a lobbyist in the position to solve a client's problem just because they're mates with a minister."

University of New South Wales senior lecturer in politics, Dr Belinda Edwards, who is writing a book centred on specific lobbying campaigns in recent years, agrees.

"The power disparity in these submission processes is clearly very important, but whether it's more important than political donations, I couldn't tell you," she says.

Professor Edwards cites the recent development of a grocery industry code of conduct – where there was "real evidence of a problem and small players putting up reasonable arguments, but in the end, the big players got what they wanted" – a voluntary code policed by the ACCC.

"All these industry groups put in four or five page submissions, then the big associations put in 20-page submissions, but then Coles and Woolworths each put in a 400-page submission and that's it," she says.

"And that's often where the data comes from that is then later used to frame the political debate – from companies that don't have lobbyists on the register, who have the resources to employ their own in-house staff to do the lobbying."

Such documents were useful to support a lobbying campaign, Mr Di Lollo says. "But you can't just dump an inch-thick pile of paper on a minister's desk," he says.

"You might have the inch-thick pile of paper for Treasury or the Productivity Commission, but then there's the three-page version for the minister's chief of staff.

"And then, if you get there, the one power point slide that if you're lucky the minister might read."

It is a more common tactic than encouraging clients to make political donations – the scrutiny donations attract is a deterrent for some.

But the submission process also builds legitimacy for any future decisions that may eventuate and, ideally, the language of the submission aligns with that emanating from the Prime Minister's Office.

But donations are a tool to be used and, Professor Edwards believes, the big donations often distract from more regular donations and perhaps more pertinently, when the money stops flowing.

Professor Edwards has looked in detail at public disclosures of donations to Labor in 2007-08, when the party was swept to power under Kevin Rudd and had proposed changes to laws on unfair contracts, financial advice and rolling back John Howard's Workchoices system.

"In 2007-08, when they came to power, they received about $85 million in donations, but once they were in power and moving on these issues, that went down to about $22 million in 2009-10," she says.

"I think it's very likely that what was happening with the political donations probably contributed to what was happening behind the scenes at the time in the Labor Party.

"It was the most dramatic exercise in a political party being financially punished by their donors we've seen in recent years.

"One of the difficulties smaller players face is getting in the room, having your voice heard, and that often relies on your ability to inflict real pain on the decision-makers.

"So if you can apply a lot of suffering, you're going to be treated differently inside the room."

Donations aside, the question of using factional influence to obtain favourable decisions is one which prompts exclamations of outrage from many of the professional players.

Such conflicts were part of the reason behind Mr Abbott's 2014 delisting of lobbyists on the register who held executive positions in political parties – a move now taken up by the NSW Liberal Party, which is reportedly pushing for lobbyists to resign from its state council.

"The difficulty around this question is that you can't ask somebody to resign from being a powerbroker where you can from the state executive," Mr Di Lollo says.

"This is the folly of what Abbott is saying – the point is not whether you hold a particular party position, the question is if you have influence over individual MPs.

"That's where I have some concerns about the way some in the lobbying industry go about their business."

Executive Counsel Australia managing director Jannette Cotterell was also concerned about the conflation of questionable characters with legitimate lobbyists playing a key role in the democratic process.

"Those people appearing in front of ICAC, they are not lobbyists, they are influence peddlers and they're there to raise money for parties," she says.

"The actual lobbyists like myself who are doing a legitimate job are actually there to help people, companies and not-for-profits to be involved in the policy process."

Ms Cotterell says it is "outrageous" that some in the industry sought to use "factional influence" as a lobbying tool, and she did not believe partisan lobbyists could easily separate political allegiance from their work.

"If you're a lobbyist and your interest is in getting a party in or out of government, then you're not acting in the interest of your client," she says.

"I would strongly caution any organisation that thought it would benefit by using a lobbyist that is politically aligned.

"It's more than just door-opening, the role of good advocacy consultants is to have a clear view of what is motivating a government and how to align (the client's) views with the agenda of that government."

While some have no concerns around political allegiance – on the condition it is separated from their professional roles – several industry insiders had concerns about un-named "shady" or "sharp" operators, but indicating such players "never last long".

In May 2014, a group of like-minded third party lobbyists formalised the Australian Professional Government Relations Association.

It is a body vice-president and Willard Public Affairs principal David Miles says was created to define and adopt a set of principles for "appropriate, professional behaviour".

It is unclear how many firms have signed on to the association's principles.

Mr Miles would not answer questions regarding the association's membership list, regarding such figures as "meaningless".

While the association allows lobbyists to participate in "the democratic process" as party members, Mr Miles says its code "states that there should be a clear separation of personal political involvement from professional activities".

Similarly, the association believed the current system "works", but was open to extending its regulatory reach.

"When the interest being represented to government is not clear, say, potentially in the instance of law firms or professional service firms engaging on behalf of their clients, then consideration could be given to including them in the registration requirements," he said. "This would mean that transparency is achieved and respected across the board."

A prime minister yet to prove he is control of his party room, a reinvigorated opposition and an 11-strong populist Senate crossbench fed by a public disillusioned with the political process.

Such is the 45th Parliament.

Ring the bells.