TORONTO - Progressive Conservative Leader Tim Hudak is standing by his plans to change Ontario's labour laws to make union membership optional, while the Liberals claim many Tories oppose the idea.

The Liberals point out several Conservative MPPs voted against a 1997 bill that would have made payment of union dues optional, including Bart Maves, now a Tory candidate in next week's byelection in Niagara Falls.

They say Hudak's proposal to make Ontario a so-called "right-to-work" province is so toxic that even many Conservatives are afraid it will cost them the next election.

Hudak no longer uses the words "right-to-work" to describe his plan, but still says he'd make payment of union dues optional.

The PC leader says he's "tired of other countries and states eating our lunch and taking away manufacturing jobs."

The Liberals also released a leaked tape from a PC policy convention last fall in which veteran Tory John O'Toole was applauded when he warned the party could be "screwed" in the expected spring election by the "right-to-work" policies.