"The real game changers [for Canberra and the region] will be international flights to the airport, a very fast rail link [to Melbourne and Sydney] and a convention centre to draw people to Canberra and position the city."

Ms Faulks, who has headed the CBC since it was formed from the union of the Canberra Business Council and the ACT Region Chamber of Commerce and Industry in October 2014, said advertisements for her replacement would appear in Saturday's newspapers and online.

While the new representative business body was working out well, there was a risk Canberra could miss out on opportunities to create its best possible future if the ACT government did not do its homework and target projects that would act as private sector enablers.

"The Federal government largesse that was showered on the ACT for decades is no longer going to happen," she said. "Canberra's future economic growth lies with the private sector."

Ms Faulks' resignation has not come as a surprise to the Canberra Business Chamber board. "My original intention was not to take on a role with the new organisation," Ms Faulks said. "I had to be persuaded and said from the start this was a short term thing.

"I saw this [the new body] as an opportunity to go to the market with a transparent process for the appointment of a new CEO."

While stopping short of saying Capital Metro and the light rail plan was a mistake, Ms Faulks is disappointed the business case followed the decision making process and not vice versa.

"I would have liked to have seen a cost benefit analysis of all of the potential routes for light rail in the staging process," she said. "Do you go to Gungahlin? Do you go to the airport, Do you go around the Parliamentary Triangle? Do you go to Belconnen? And then [make] an objective decision around the staging of those."

Ms Faulks agreed the CBC, which has admittedly been preoccupied with the recent merger and restructure, had been quiet on light rail.

"The organisation, given this was a fait accompli, has been relatively silent on Capital Metro because right up until the end of last year there was no cost benefit analysis, no business case, for us to make an objective assessment on," she said.

The absence of data was unfortunate given most ACT business people believe a convention centre offers a better return to the community than light rail.

This is borne out by an Ernst and Young and Associates study commissioned by the CBC that sets the convention centre cost benefit ratio at $2.40 for every $1 invested as opposed to $1.20 for Capital Metro.

"We are just about to give our figures to the ACT government," she said. "The [former] Canberra Business Council canvassed the Canberra business community a couple of years ago and almost unanimously they agreed that the top infrastructure priority for Canberra was a new convention centre.

"We had 45 industry bodies, all of the research and learning institutions, all of the tourism assets in Canberra, all supported that [the convention centre] as the number one priority."

Ms Faulks said that unlike Capital Metro a convention centre would spread money around.

"Convention centres don't make money," she said. "What they do though is that everybody who attends a convention or a conference spends about $500 a day in the city in hotels, restaurants, retail and whatever. You actually inject a lot of money into the economy."

Ms Faulks has been representing Canberra's business community since 2007 when she was appointed chief executive officer of the Canberra Business Council.

Andrew Blyth, the former chief executive of the ACT Region Chamber of Commerce and Industry, resigned from that post in August 2014.