Unions representing the public service are warning the federal government to leave their pensions alone, as the government looks for areas to cut spending and gain control over a massive deficit.

Prime Minister Stephen Harper made a 10-member cabinet shuffle on Tuesday, saying the government's primary focus is the economy and identifying ways to tighten spending.

The new leader of the Treasury Board, who oversees the public service, will play a critical role in finding ways to cut back the government's $56-billion deficit, Harper said.

Unions fear cutbacks

Union leaders happened to be meeting in Ottawa on Tuesday when they learned Harper appointed Stockwell Day to head the Treasury Board, tasking him with a major role in finding areas for the government to save money.

The unions say if the government plans to tamper with their pensions, they should be ready for a fight.

"The membership of the Public Service Alliance of Canada and indeed the membership of all the bargaining agents who are in this room are going to stand up and take this on if they try and tamper with the pensions," said John Gordon, president of the Public Service Alliance.

The unions say they don't want to see a return to the mid-1990s when the government slashed spending and cut programs to tackle the deficit.

Public service connection?

A Carleton University professor says the new president of the Treasury Board likely won't be as in touch with the needs of the public service as past leaders.

"It's fair to say Mr. Day won't be as attuned to the City of Ottawa as compared to say John Baird. He probably won't be particularly attuned to the public service, but I think more importantly, he'll do whatever the prime minister wants him to do," said Jonathan Malloy.

The cabinet shuffle follows the resignation of former Veterans Affairs minister Greg Thompson.

With a report from CTV Ottawa's Norman Fetterley and files from The Canadian Press