The Community and Public Sector Union says that 90 per cent of its 14,000 members at the department will vote no, according to its poll and with several hundred non-union members also taking part, 76 per cent of them indicated they would reject the deal, with about 13 per cent undecided.

The union released the poll results on Wednesday morning ahead of an expected announcement of a yes-vote to an agreement at the 1200-strong Infrastructure Department.

Last month, the 34,000-strong DHS followed other agencies in offering a 1.5 per cent a year pay rise, after a softening earlier this year of the government's strict instructions to departmental bosses on wage rises and conditions.

Demands for longer working hours and changes to carers' and other leave entitlements were also dropped.

The terms are a big improvement from the .8 per cent offered in February, linked with a range of unpopular "productivity offsets", in a proposal that was abandoned without even going to a vote.

But the union says the poll, of 7300 union members and 430 non-members, shows the new offer is in trouble before an all-staff ballot has even been scheduled.

CPSU Assistant National Secretary Michael Tull said the disagreement now had more to do with proposed cuts to conditions and entitlements than wages.

"This poll shows an overwhelming majority of DHS think the cuts to rights and conditions in proposed agreement are unacceptable," the union official said.

"Members are telling us they are voting no to protect their right to reasonable working hours, to have access to a union delegate, and to protect their take home pay from cuts to allowances.

"From the beginning of this bargaining process, the Abbott Government has tried to portray public servants as greedy, faceless, Canberra 'fat cats'.

"But the average DHS employee is a part-timer, who lives in the suburbs, works hard for their below average wage and has never been near a helicopter.

"Why does this Government think it's okay to attack the rights and conditions of average working mums and dad?"

Nine enterprise agreements have now been voted up under the government's bargaining policy at agencies including Treasury, the Australian Public Service Commission, the Australian Transport Safety Bureau and Communications.

Most of the agreements that have been accepted have contained pay rises at or close to 4.5 per cent over three year.

But big challenges remain with none of the large service delivery agencies like the ATO or Human Services, where many of the of the public service's "frontline" staff work, having reached agreement.