TORONTO -- Some of the biggest public sector unions expect to be butting heads with the Ontario government in the coming months as they push for wage increases from an administration standing firm on a "net zero" target.

Bargaining is getting underway between the province and unions representing public servants, teachers and school support staff as well as provincial police, whose contracts have expired and are up for negotiation -- several for the first time since the end of mandated wage freezes.

But the province is still looking for a net zero increase for public sector workers amid its pledge to eliminate a $12.5-billion deficit by 2017-18.

Treasury Board president Deb Matthews said the government has been clear that any wage increases right now will have to be offset by savings in other areas.

"We recognize that these are tough negotiations in a tough fiscal environment and we all have to do our part," a spokeswoman said in a statement.

Provincial police start bargaining Monday and the head of the police union calls zero sum bargaining "totally unrealistic."

After a couple of years of pay freezes, the provincial police received an 8.5-per-cent wage hike last year based on a "catch-up clause" that allowed them to receive pay equal to the highest-paid police service in the province.

They will "absolutely" be looking for another increase this year, though they're not seeking a catch-up clause this time, said Jim Christie, president of the Ontario Provincial Police Association.

"We understand that we did not cause in any way, shape or form the fiscal hardship that Ontario has got themselves into, but obviously as employees we are sort of in the firing line when it comes to trying to repair the damage that has been caused," he said.

The province is already facing labour disruptions.

About 3,000 nurses at community care access centres went on strike Friday, saying they were seeking "very small wage increases" following a two-year freeze. And public servants, represented by the Ontario Public Service Employees Union, have been staging protests and their union president has raised the spectre of a strike.

OPSEU president Warren "Smokey" Thomas said workers are looking for a "modest" salary increase, perhaps around 1.5 per cent.

"That's not outrageous, considering they haven't had a raise for two years," he said.

But in addition to a net zero wage increase, which he calls "manageable," Thomas said the government is asking for various concessions, including prolonging the length of time to get to the top of the pay scale and starting new hires at five per cent less.

And then there are the teachers.

The last time the Liberal government imposed a wage freeze, teachers withdrew from extracurricular activities, engaged in work-to-rule campaigns and protested in the streets. Unions representing teachers and school support staff are challenging the legislation in court.

Premier Kathleen Wynne eventually reopened the contracts for public school teachers, which the auditor general said cost Ontario taxpayers $468 million.

The teachers and support staff have been without a contract since the summer, and a resolution may not come quickly. The Elementary Teachers' Federation of Ontario has been given a strike mandate by its members as negotiations start. The union would not comment, but their bargaining website shows they are looking for "improvements to teacher compensation."

The major negotiations with various public sectors come at a time when the province imposed a cut to fee-for-service payments to doctors -- which takes effect Sunday -- after year-long negotiations with the Ontario Medical Association failed to produce an agreement.