TORONTO -- The Ontario government passed legislation Thursday to prevent a strike or lockout at a utility that generates roughly half of the province's power, saying it could not risk letting labour action disrupt the electricity supply.

Legislators were called back from the holiday break on Monday in an effort to end the labour dispute between the Power Workers' Union and Ontario Power Generation.

The Progressive Conservatives said their bill will send the matter to arbitration so it can be resolved after months of deadlock between the two sides.

Its passage "removes the risk of widespread power outages and allows a dispute resolution to happen appropriately," Energy Minister Greg Rickford and Labour Minister Laurie Scott said in a statement.

"The people of Ontario can be assured this holiday season that they will have the power they need to light up and heat their homes and businesses."

Premier Doug Ford, who has been largely absent from the legislature this week, was not present for the final vote on the bill. Ford's office said he was meeting with stakeholders on various issues throughout the week, but opposition legislators said the premier should show up to vote on the bill he championed.

"If they're all yelling (that) it's an emergency, why isn't he in his seat?" said Interim Liberal leader John Fraser.

NDP Leader Andrea Horwath suggested the premier could have rearranged his schedule. "It was last minute for all of us but we all managed to be here to do our jobs," she said.

New Democrats have also accused the Tories of fear-mongering for immediately turning to back-to-work legislation when there were less drastic options available.

Some Liberals as well as Green party Leader Mike Schreiner voted in favour of the bill, though both parties said they disapproved of the way the Tories handled the situation.

"I understand my colleagues' support of collective bargaining, but in a choice between collective bargaining rights and public good and public safety, public good and public safety always trumps," Fraser said.

Schreiner said the government was trying to have it both ways by preventing the power workers from striking but stopping short of declaring them an essential service.

"I actually think that's the direction we should go. Electricity is an essential service, people rely on it for heating their homes, in particular in rural areas," he said.

"I know the government is probably reluctant to do that because it probably means (power workers) will have higher awards from arbitrators if that's the case, but if the government is going to proceed in the way they have then clearly electricity is an essential service."

The union, meanwhile, has said it is disappointed with the government's decision, which it says undermines bargaining efforts.

The labour group, which represents about 6,000 OPG employees and another 10,000 energy sector staff, has been without a collective bargaining agreement since March 31.

The legislation's passing means the house is adjourned until February, unless it is recalled before then.