Figures from the public service commission, released on Monday, also showed about 40 per cent of public servants remained without a new workplace deal four years after bargaining started, as 19 agencies were yet to settle their industrial disputes.

The commission's State of the Service Report for 2016-17 showed casual staff were shown the door along with ongoing employees as the public service shed 3,600 workers last year and reduced its headcount to 152,095.

Agencies cut their casuals after years bolstering their ranks, even while shedding permanent workers during the height of the APS' rationalisation between 2013 and 2015.

The APSC on Monday said recent cuts to non-ongoing staff were related to natural attrition of a temporary workforce hired for the federal election and the census during 2016.

Casual staff numbers have consistently risen since 2006, from about 1,000 a decade ago to more than 9,000 last year.

The main public sector union said while the number of casuals in the public service had dipped, it remained too high and significantly above the level when the Coalition came to power.

Community and Public Sector Union national secretary Nadine Flood said the report didn't paint a true picture of casual employment because people hired through labour hire or contracting arrangements were not included in its figures.

"This government has a proven track record of outsourcing - paying more to private companies while the people actually doing the work are paid less and work under inferior employment conditions with little or no job security," she said.

In 2017, 90 per cent of APS employees were employed permanently and agencies slashed their casual staff by more than 1000 across the government.

The APSC said while permanent staff would continue to make up the bulk of its workforce to guarantee continuity in knowledge and skills, a flexible workforce including casual workers would be needed more as "many dimensions of work became more complex."

"The right mix of employment categories will become more important as the APS embraces new policy and service delivery challenges," it said.

While nearly 60 per cent of the public service's workforce were women, a majority of staff in senior leadership roles were men. Among higher levels, women outnumbered men at only the EL 1 classification.

"EL 2 and SES roles still require further effort as the APS continues working towards parity," the report said.

As public servants at the Federal Court and other government services and agencies remain locked in industrial battles, the commission said agreements negotiated so far - including 39 in 2016-17 - had "sensibly" balanced the interests of agencies and staff.

However it expected all agencies would resolve their workplace disputes this financial year.

The report said confidence in agencies' handling of performance management was low across the public service.

For the first time in five years, the percentage of public servants working in Canberra compared to interstate grew, rising slightly to 37.9 per cent despite momentum this year within the Coalition to decentralise departments and move staff into the regions.

Most public servants surveyed were positive about their immediate supervisors (81 per cent), but many were less glowing about their SES manager as fewer (61 per cent) said they were of a "high quality".