Workers at the Commonwealth's largest department, Human Services, voted by an overwhelming 83 per cent to 17 per cent to reject a 1.5 per cent pay deal in a result that will be felt across the 160,000-strong Australian Public Service.

Unions are now vowing to step up their campaigns of industrial action as tens of thousands more public servants at the Immigration Department and the Australian Taxation Office prepare to go to the polls in coming weeks.

In other results announced on Friday, public servants at two more agencies voted decisively to reject wage proposals but 2600 Department of Social Services staff voted by a narrow 52 to 48 per cent margin to approve the deal they had been offered.

The 3600-strong Department of Health voted by a margin of 61 per cent to 39 per cent to reject an offered pay increase of 1.5 per cent in a result announced on Friday morning.

Staff at Intellectual Property regulator IP Australia rejected a similar offer by an even larger margin of 73 per cent.

The result comes on the back of a decisive no-vote at Veteran's Affairs this week. Department of Veterans' Affairs workers voted by a margin of 61 per cent to 39 per cent, with 1587 of the department's 1920 public servants casting ballots.

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The spiralling number of no-votes means that Public Service Minister Eric Abetz is confronted with an industrial stalemate with the nation's bureaucrats with more disruptive strike action in frontline agencies looming.

The minister's office did not respond to requests for comment.

But Community and Public Sector Union national secretary Nadine Flood said the results would be followed by a fresh wave of industrial action.

"The DHS ballot result comes ahead of a new round of industrial action which kicks off with a half-day strike on September 15 involving Canberra-based members from agencies including Human Services, the Tax Office, Immigration and Border Protection and Employment," Ms Flood said.

"This action will be followed in coming weeks by further strikes and industrial action around Australia which will affect service centres, call-centres, international airports, ports and a range of other public service workplaces."

The union leader said the ballot results announced on Friday left the government's public sector wage policies in tatters.

DHS' general manager of communications Hank Jongen said the department would now return to the bargaining room.

"The department will now seek staff feedback and return to the bargaining room," he said.

"We will resume negotiations with bargaining representatives and continue bargaining in good faith, however this process will take time."

At Social Services, Departmental Secretary Finn Pratt frankly acknowledged the yes-vote had scraped home.

"The results tell me that while the yes vote prevailed, there were many of you who did not support the offer," Mr Pratt wrote in an all-staff email.

"I would like to assure you that we will work with all of you to ensure that you are included in our consultation processes and mechanisms as we move to implement the EA.

"I hope that you will also see the benefits of having one agreement in place."