Workers at Ontario's government-run liquor stores have voted to go on strike if upcoming contract negotiations fail to produce an agreement.

The results of the three-day vote were announced Saturday by the Ontario Public Service Employees Union. About 3,670 of the union's 6,000 members cast ballots, with 93 per cent of them favouring strike action to back their demands.

The union and the Liquor Control Board of Ontario are set to begin bargaining on Tuesday. The last contract expired at the end of March.

Union spokesman Randy Robinson said negotiations are expected to go on for several weeks before the possibility of a strike arises.

The union said the main issue from its standpoint is a decline in the number of full-time positions and an increase in lower-paying part-time jobs and contract work with little job security.

It said about 60 per cent of LCBO workers are casual employees who earn about $20,000 a year on average.

"For a rich, rich employer like this, it's just not acceptable," Robinson said.

"What kind of Ontario do we want when it comes to the kind of jobs that we have in our communities? Are we going to have part-time, temporary, casual disposable jobs that nobody can live on? Or are we going to have decent, full-time, permanent jobs that people can raise a family on, or buy a house on, or retire on," he said.

The LCBO maintains that contract and part-time positions are necessary for the operation of the business.

Demand fluctuates throughout the year and stores need more staff at peak periods, like the winter holidays and the warm summer months, and fewer staff during slow periods, said Chris Layton, an LCBO spokesman.

"The amount of staff is relevant to the amount of business that you have," he said. "In other words, you would have all this staff and you wouldn't have the business."

With files from The Canadian Press