The public service's biggest department and unions are approaching a showdown as 34,000 workers at the Department of Human Services (DHS) prepare to vote early next month on a new pay deal.
Tax Office bosses want another 18,000 public servants working there to follow their DHS counterparts to the polls three weeks later.
The struggle at DHS, which has become a key battleground in the broader public service wage dispute, will come to a head with a vote on September 7, 14 months after the last agreement expired.
DHS has the strongest union representation of any federal department and the most casual, part-time and lower paid public servants, and the result of the vote will be keenly watched across the 160,000-strong service.
Nine enterprise agreements have now been voted up under the government's bargaining policy: three at NBN Co, and one each at ComSuper, the Australian Office of Financial Management, Treasury, the Australian Public Service Commission, the Australian Transport Safety Bureau and Communications.
But there have been surprising rejections, at the Industry Department and Attorney-General's, and peace looks a long way off in the largest agencies, Defence, the Tax Office, Immigration and DHS.
The Community and Public Sector Union (CPSU), which needs a strong no-vote at DHS to maintain the momentum of its campaign across the service, has been working hard to persuade its members to reject the offer.
The department has pointed out the new terms on offer, including a 1.5 per cent annual wage increase, are a big improvement on the 0.8 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.
The new deal contains a performance-based salary advancement for eligible staff of 1.5 per cent per year in 2016, 2017 and 2018, and others would receive up to 2.75 per cent salary advancement in 2015.
The department says the deal that has been offered has been designed to meet a complex set of requirements.
"We have worked hard to develop a proposal that addresses the key concerns of our staff, the department's operational requirements and meets the Government's bargaining policy," a DHS spokeswoman said.
But the union, which has conducted polling predicting a big no-vote, is not to be swayed.
CPSU deputy national president Lisa Newman said the vote is going to be a setback for public service minister Eric Abetz.
"DHS workers are not going to allow their rights, conditions and take-home pay to be ripped away," Ms Newman said.
"This agreement will be rejected by workers because the offer still contains cuts to important conditions that workers rely on and the proposed pay increase falls short of covering the loss from the cuts.
"The CPSU has polled workers in DHS – including non-members – and we are seeing an overwhelming intention to reject this unfair agreement that strips away workplace rights and conditions.
"Workers have been saying for months that they will vote no to protect their rights to reasonable working hours, access to union delegates, and protecting their take-home pay from cuts to allowances."