However, the former under-treasurer does not see his new role as that of a police officer, or believe it is about finding fault.

Rather, he sees the role of the auditor as more diagnostic - looking for underlying problems and finding ways to make systems healthier.

It's a job he sees as integral to the wellbeing of democracy, which he says has been rattled in recent times.

"I have a very strong, long-standing commitment to the benefits and strengths of the democratic systems we have in this country; the parliamentary systems and the checks and balances embedded in that have stood the test of time. It's been shaken a few times but the inner strength of the system has been paramount," Mr Harris says.

"In many respects, right across the country at the moment it is under challenge, and in my view the role of senior officers within that system such as the Auditor-General, the Ombudsman and other officers of the parliament who have statutory roles [is to be] committed to ensuring proper process, good government and good governance is maintained and vigorously defended."

Much has been said about Mr Harris since his appointment last year. Former colleagues have described him as straight, measured.

As a former under-treasurer and Chief Minister's Directorate head in the early years of the Stanhope government, he knows the ACT Public Service inside and out, and knows what questions to ask.

He says the ACT Public Service has a "good reputation" for upholding standards, and it's his job "to ensure that stays the case".

He comes back to the territory from his native Tasmania, where he was most recently chair of Metro Tasmania's board and independent chairman of the review of the Tasmania Fire Services Act.

While he spent about eight years in the private sector - some of that time as the executive director of the Australian Automobile Association in Canberra - he has more than three decades of experience in the public service.

He grew up in Hobart, studying economics before beginning his career with the Tasmanian public service in 1983.

He worked in the departments of treasury and public transport, before he was recruited to be the director-general of transport in the Western Australian government in 1995.

In early 2002 he moved to the ACT for the under-treasurer job, where he worked under Ted Quinlan.

The issues they looked at back then echo today - trying to balance the budgets in a small, revenue-restricted jurisdiction and looking at better ways to manage the rates and land tax system.

That an Assembly inquiry into commercial rates is unfolding during our interview doesn't surprise him.

"Some things never change," Mr Harris says.

He also knows former auditor-general Dr Maxine Cooper well from his time in the ACT government.

He says people can expect from him "a continuation of Max's view of the world", although he has a particular interest in performance auditing - getting the best out of government and the best value for taxpayers.

"I don't see auditing as a policing role. It's about ensuring compliance and about ensuring true and fair perspective on information that's being presented," Mr Harris says.

"It’s a partnership arrangement between the auditor and those being audited; we’re not acting as policeman or finding fault, we’re acting collaboratively to find ways of improving outcomes for organisations and taxpayers."

His method of operation is to "actively listen and make a judgement on the basis of fact".

"I share my views and thoughts with those I'm interacting with. I don't like secrets and I don't run a secret agenda. I'm an open, collaborative person. Those I'm auditing should expect openness, transparency through the process. That's what people can expect from me."

Don't mistake that for softness, or leniency though.

"I have very strong personal views in relation to ethical behaviour," Mr Harris says.

With his history in transport, Mr Harris has a keen eye on the light rail contract, which is already a part of the audit office's forward program.

"It's obviously one of the biggest contracts around at the moment and light rail and transport-related projects are always interesting to examine," Mr Harris says.

"A contract as large as light rail gives an opportunity after the event to look at what was done well, what could be improved and what learnings can be taken from that improvement."