Battle lines are being drawn ahead of pay negotiations within the Prime Minister’s department.

Over 2000 public servants at the Department of the Prime Minister and Cabinet (PM&C) will vote next week on a pay deal, but department managers and the CPSU appear to be a long way from any resolution.

The Federal Government’s bargaining policies have not served it well in the last year, with a long series of high-profile pay proposal rejections showing the resoluteness of government workers.

The path to a new deal in the upcoming negotiations at PM&C looks just as difficult as at other departments, with the two sides unable to agree on even the figures in the offer.

Department bosses say they have worked hard to put together a deal that is fair to the 1700-odd public servants drafted into PM&C when former prime minister Tony Abbott dramatically expanded the operation.

But the Community and Public Sector Union (CPSU) wants its members to say no, issuing a bulletin to PM&C staffers that claims the offer would impose conditions that are more harsh that the government framework calls for.

“Employees are telling us they are voting 'No' to the proposed offer because it significantly cuts your conditions, going even further than the harsh and unworkable Government Bargaining Policy, has an unreasonable pay and classification structure that damages your career progression [and] severely cuts your current performance-based incremental advancement arrangements,” the bulletin states.

The unions has also expressed dismay at the pay rise it claims is below 1.2 per cent a year, as it would come in well under the 1.5 per cent offered to other departments.

PM&C rejects this claim.

“The offer is an average of 4.5 per cent over three years and is consistent with the government's bargaining policy,” a spokesperson told Fairfax, but reportedly would not elaborate further.

The union also says plans to “streamline” some terms and conditions from the last agreement will leave workers worse off.

“[The offer] does not compensate for the delays caused by MoG exceptional circumstances and government delays [and] moves many of your hard fought and won conditions into easily changeable policy,” the union’s bulletin reads.

“Remember, when you are voting on the proposed EA you are NOT voting on the policies, which have been stripped out.”

PM&C is sometimes considered a watermark department within the federal public service, so the outcome of the poll next Monday will be closely watched.

The Coalition's tough public sector bargaining framework has lefts tens of thousands of workers across the 152,000-strong public service locked in a stalemate, as staff reject unworkable deals.

But department bosses say they say they cannot make better offers under the framework.

Public service Minister Michaelia Cash has recently indicated that she is willing to meet workplace unions to talk about ways to end the crippling impasse.