The Progressive Conservatives' call to make Ontario a so-called "right-to-work" province is "misguided" and would mean lower salaries and a weaker economy, the Liberals and New Democrats have warned.
"It just doesn't reflect Canadian values," Labour Minister Linda Jeffrey said in an interview.
"I believe it would mean lower wages and reduced buying power, and would have a very serious effect on the economy."
The Conservatives said Ontario currently has what they call "forced unionism," and they want to give people the right to decide whether or not to join the union at their workplace and pay dues.
A right-to-work law would make Ontario a more attractive place for businesses to invest in instead of seeing new companies go to other jurisdictions with more welcoming rules, said deputy PC Leader Christine Elliott.
"What we really need to do is develop a very nimble workforce and that's what the right to work legislation is intended to do, so that businesses when they need to adapt to changing conditions in the workplace, they have the flexibility to be able to do that," she said.
The Tories said U.S. states that adopted right-to-work laws create more jobs and workers get higher raises, but Elliott struggled when asked if she could point to one such jurisdiction where wages actually went up.
"I don't think that there's any situation where Ontario's exactly the same as other jurisdictions, so I don't think you can provide that kind of comparison," she said.
The New Democrats called right-to-work laws "wrongheaded," warning such a move would not help Ontario's economy because no one would have any money to spend.
"Driving down wages and turning Ontario into the next Alabama is simply a recipe for more people being squeezed out of the middle class, more hardship, and it will not stimulate the economy because people won't have any money to spend," said NDP Leader Andrea Horwath.
"I don't see how the removal of people's ability to make a decent wage, have decent benefits, be able to retire with dignity, is somehow made more beneficial in a right-to-work state."
The Tories cited a 2012 study from the Pacific Research Institute in San Francisco that showed U.S. states with right-to-work laws saw 11 per cent higher economic growth and 11 per cent higher personal income growth compared with other states.
"The overall issue I believe will result in people earning higher wages because we will have more businesses locating here, they will do well and be able to hire more people and pay higher wages," said Elliott.
"But if we have a situation where they're unable to move and respond to international demands and conditions, then we're never going to be able to compete with the rest of the world in attracting those businesses to Ontario."
Jeffrey said one of her "worst days as minister of labour" came last February, when U.S. heavy equipment giant Caterpillar closed the Electro-Motive plant in London, Ont., and relocated to Indiana -- a right-to-work state -- after workers refused to accept a 55 per cent cut in wages and benefits.
After Michigan became the 24th U.S. state to pass a right-to-work law Monday, President Barrack Obama said it wasn't about the economy.
"These so-called right-to-work laws, they don't have anything to do with economics, they have everything to do with politics," Obama told cheering workers in Lansing, Mich.
What they're really talking about is giving you the right to work for less money."