Construction workers, building security guards and cleaners who are under government contracts would receive a "fair" wage under new legislation Ontario's governing Liberals will introduce Tuesday and hope to pass before the June provincial election.

The new legislation -- called the Government Contract Wages Act -- would establish minimum pay rates for workers in those sectors and require contractors and subcontractors hired by the government to abide by them.

"It means that if you work on a government project ... you will be paid fairly. Full stop," Premier Kathleen Wynne said as she made the announcement at a union training facility for plumbers and steamfitters in Toronto. "This is about preventing employers from undercutting workers wages in order to lowball on provincial projects."

Wynne said the bill will update fair pay legislation that has remained unchanged since 1996. Trade organizations have lobbied the government for the update for years and the Liberals have spent the past 12 months consulting with stakeholders, she said.

"We're tabling legislation to enshrine the principle of a fair prevailing wage in law as well as provide the necessary support and enforcement to make it work," she said.

Patrick Dillon, the secretary treasurer of the Provincial Building and Construction Trades Council of Ontario, said the legislation will not only help protect worker wages but ensure safety on the job.

"When contractors are bidding and one is lowballing the other, they have to cut some place and generally they start to cut at health and safety," he said. "We think this is a big step in the right direction to help with prevention."

Dillon acknowledged that the move may not be popular with all contractors in the province.

"Some contractors may complain about this," he said. "But their workers, for sure, will not be complaining."

The move comes months after the government passed major labour reforms that included minimum wage hikes -- it jumped to $14 an hour on Jan. 1, and will rise again to $15 on Jan. 1, 2019 -- and equal-pay measures for part-time and casual workers.

Wynne said she was optimistic the new bill would become law before the election, slated for June 7.