The Community and Public Sector Union (CPSU) claims 2,800 public service jobs have already been cut and more will be lost as part of next week's federal budget.

The union claims around 30 agencies have so far been affected, with human services losing around 470 positions.

The reductions are part of efforts to meet the Government's increased efficiency dividend for the upcoming financial year.

CPSU national secretary Nadine Flood says she expects more announcements about job losses will be made in the federal budget.

She says the public service is paying the price so the Government can deliver a political promise.

"The Government's single-mindedness about delivering a budget surplus is having a really negative impact," she said.

"We are looking at significant cuts in front-line jobs and services.

"That's going to impact on communities and it's going to impact on business and industry that rely on those services."

Ms Flood says the announced cuts are already having a serious impact on workloads.

"What we've seen for example in human services, Centrelink and Medicare, is waiting times blow out dramatically," she said.

"People are waiting up to three to four weeks for just an appointment to actually be able to talk to someone."