Up to 6 per cent of staff in organisations including Defence, Agriculture, Social Services, Comcare and Defence Housing report witnessing acts of cronyism, nepotism, fraud, forgery, embezzlement and undisclosed conflicts of interest.

And one in 10 think it would not be hard to get away with behaving corruptly in their workplace.

But almost two-thirds say they have not reported dodgy behaviour because they think no action will be taken or it could hurt their career or have other adverse consequences.

The disclosures were made in a census of more than 136,000 Commonwealth bureaucrats undertaken by the Australian Public Service Commission in May and June this year, and released in its State of the Service Report on November 26.

The findings come amid political furore over a New South Wales police investigation of the office of federal Energy Minister Angus Taylor over the distribution of false documents purporting to show Sydney City Council travel expenses, and a subsequent call by Prime Minister Scott Morrison to NSW police commissioner Mick Fuller to discuss the probe.

They also put the spotlight on the Government's proposal for a Commonwealth Integrity Commission.

Under the Government's plans, the Commission would have two divisions - one focused on law enforcement and the other on the public sector, covering the APS, parliamentarians and their staff, contractors and the staff of federal judicial officers.

Attorney-General Christian Porter told Parliament yesterday that a draft Bill to establish the Commission would be released for public comment "early next year or later this year".

Critics say the Government's model is flawed because the public sector division lacks teeth to properly pursue and investigate allegations of corruption.

Monash University senior lecturer in law, Dr Yee-Fui Ng, said that, unlike state corruption fighters such as NSW's Independent Commission Against Corruption, the proposed CIC would have to establish reasonable suspicion of corruption before it could launch an investigation, which is "a much higher threshold".

Dr Ng warned that cases like that involving disgraced former NSW Labor MP Eddie Obeid would be unlikely to be investigated by the proposed CIC because it began with anonymous allegations rather than established suspicions of criminality.

Griffith University law professor and board member of Transparency International Australia, AJ Brown, the types of behaviour observed by public servants, such as nepotism, cronyism and conflict of interest, were "classic indicators of gray area corruption".

"It might be arguable whether it is criminal, but it is definitely seen in environments where more serious corruption risk is high," Professor Brown said.

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He warned that if the Government's CIC did not encompass gray area corruption then "the new system is going to be poorly calibrated from the start".

Dr Ng said it was unlikely much potentially corrupt behaviour of the kind identified in the APS census would be investigated by the Government's proposed anti-corruption watchdog.

"If you are raising the bar to that criminality level that means a lot of allegations will not be investigated," she said.

According to the APSC report, 176 public servants were investigated for corrupt behaviour in 2018-19, the highest number in five years. Of these, 107 were alleged to have engaged in fraud, forgery or embezzlement. An unidentified agency accounted for most of the cases, the Commission said, adding that the low incidence of identified corrupt behaviour was evidence that a "pro-integrity culture remains strong across the APS".

It said a steady decline since 2016 in the number of public servants being investigated for breaches of the APS Code of Conduct showed the effectiveness of measures to improve integrity.

"The proportion of respondents to the APS employee census who feel confident they would know what to do if they identified corruption in the workplace also continues to improve (83 per cent in 2019, up from 70 per cent in 2015). This indicates that efforts by agencies to raise awareness of Code of Conduct matters, including corruption, are effective," the Commission said.

But the census reveals that many more instances of potentially corrupt behaviour may be going unreported.

Overall, 4299 public servants who took part in the census thought in the previous 12 months they had witnessed actions by a colleague serious enough to be viewed as corruption.

Of those, almost two-thirds decided not to report it because they felt no action would be taken, the behaviour was accepted by managers, or blowing the whistle could hurt their career or have other adverse consequences.

A further 12 per cent said they did not know how to report corruption.

Professor Brown said the results "confirm what we already know, and that Commonwealth Governments of both political persuasions have denied, that there is at least as real a risk of corrupt behaviour in the Commonwealth as in any other government".

Six per cent of employees at Comcare, Defence Housing, the Department of Agriculture and Water Resources and the Department of Veterans Affairs who took part in the census reported witnessing corruption in the previous 12 months, most commonly cronyism and nepotism.

More than one in 10 thought it would not be hard to get away with such behaviour.

Dr Ng said these were surprisingly high numbers and were a cause for concern.

"The fact that this is coming from inside the public sector, that these are insiders who know the actors, it is not a good sign," she said.