Ontario's Liberal government is moving to introduce back-to-work legislation that would end a nearly five-week strike by college faculty, though opposition from the NDP means it may not happen quickly.

Premier Kathleen Wynne said unanimous support of the legislation would have meant students could return to class on Monday morning.

"We have said repeatedly that students have been in the middle of this strike for too long and it is not fair," she said in a statement. "We need to get them back to the classroom."

But the NDP blocked a government attempt to table the bill by refusing unanimous consent to allow the Liberals to do so Thursday evening after the normally scheduled time period for introducing legislation.

Some 500,000 students have been out of class since the strike by 12,000 college professors, instructors, counsellors, and librarians, began Oct. 15. It is now the longest strike in colleges' history in Ontario.

The legislature will now reconvene Friday, when it does not normally sit, and the Liberals will again try to introduce the legislation in the afternoon. If it is again blocked, they say they intend to sit through the weekend.

NDP House Leader Gilles Bisson said his party has never supported back-to-work legislation.

"In the end, the government has the tools," he said. "It can do what it has to do in order to be able to pass this legislation over the weekend."

Advanced Education Minister Deb Matthews said with unanimous consent the legislation could have been introduced and sped through first, second and third readings Thursday night.

"We could have done it in 10 minutes and then students would know they're back in the classroom on Monday," she said. "It was very disappointing that the NDP decided to block it."

The legislation would have to pass Friday for the province's 24 colleges to prepare for classes to resume Monday, Matthews said.

The College Employer Council, which represents the colleges, said it supports the introduction of back-to-work legislation as soon as possible.

The president of the Ontario Public Service Employees Union, which represents the striking faculty, said Thursday morning that he would not support any back-to-work legislation.

"From my perspective, if they do that, the labour movement has to oppose that," said Warren (Smokey) Thomas. "Labour rights are enshrined in law and to this point in time they've respected the collective bargaining process."

Wynne had asked the colleges and the union to return to the bargaining table Thursday after workers voted to reject a contract offer, but within several hours the two sides reached an impasse when they could not agree to binding arbitration.

OPSEU had recommended the colleges' contract proposal be rejected.

The colleges have said the offer included a 7.75 per cent salary increase over four years, improved benefits and measures to address concerns regarding part-time faculty, with language surrounding academic freedom remaining as the only major outstanding issue.

But the union said the offer contained "serious concessions" that were not agreed to, which would erode faculty rights and contribute to an unsustainable staffing model.

Under the proposed back-to-work legislation, the strike would end and all outstanding issues would be referred to binding mediation-arbitration.