The spending habits of top public servants are "flying under the radar", according to one expert, but they could soon be in the spotlight in the wake of the Bronwyn Bishop expenses scandal.
Australia is "nowhere near best practice" in scrutinising the travel and expenses of top mandarins, with the system lacking transparency and in need of reform, former Finance Department deputy secretary Stephen Bartos says.
The Prime Minister's review of the expenses system for politicians, announced on Sunday as the Speaker resigned after three weeks of scandal about her spending, will also look at the arrangements for more than 200 departmental secretaries, agency heads and other officials.
Former Finance Department chief David Tune and Remuneration Tribunal president John Conde will lead the review which will try to find a new way to administer parliamentary entitlements.
But they will also look at the entitlements of about 215 public officials whose salaries and allowances are subject to Remuneration Tribunal determinations.
Departmental secretaries, some of whom are paid annual salaries of more than $700,000, currently sign off on their own claims for domestic travel and expenses, with overseas travel subject to ministerial approval.
Mr Bartos, who is now a public policy consultant with ACIL Tasman, says the system could get a lot better.
"We're nowhere near best practice in that there's a low level of transparency," he said.
"The current system leaves it largely up to departments.
"There is the overarching control that expenditure must be efficient, effective and ethical under the legislation and there is the control that these things are subject to internal audit.
"But they don't tend to be subject to external audit because, in essence, they're not big expenses by comparison with Commonwealth expenditure or even other areas of departmental spending.
"So they tend to fly under the radar.
"If a departmental secretary wants to fly all over the country, they just decide it."
Mr Conde and Mr Tune have been given terms of reference allowing them to look at models operating overseas and may look to New Zealand where last month public service chief executives began making their expenses bills public as part of efforts to promote more transparency in the sector.
Mr Bartos said he was "absolutely" in favour of reform to Australia's system but that it did not have to be complicated.
"The only reform that is required is transparency," he said.
"If expenditure is transparent, it controls itself.
"If people know they're going to be subject to scrutiny by other people, they act in a way that's proper."
Mr Bartos said there was much Australia could learn from its trans-Tasman neighbour about governance in areas other than expenses and entitlements.
"New Zealand is well ahead of Australia on public admin issues," he said.