OTTAWA — A union representing public service workers says it "will not stand idly by" for measures outlined in Finance Minister Jim Flaherty's fiscal update.

Flaherty's mid-term economic statement includes a plan to cap public service raises to 2.3 per cent this year and 1.5 per cent annually the next three years and temporarily remove the right to strike in the public service.

The Professional Institute of the Public Service of Canada calls it a "simplistic, ideological" update that tramples workers' rights enshrined "both in the Constitution and in our social fabric."

The union, which represents 55,000 professionals and scientists, also says the government should invest directly in the economy instead of "using the public service as a scapegoat."

Opposition parties are also incensed with the fiscal plan and are threatening to topple Stephen Harper's Conservative minority. They have begun informally exploring the idea of cobbling together a governing coalition.

The Liberals, NDP and Bloc Quebecois said they can't support the plan because it offers no stimulus package to deal with the economic crisis.

It also contains a vow to scrap public subsidies for political parties that would financially cripple every party except the Tories.