TORONTO - Ontario Premier Dalton McGuinty said Tuesday he's "more than prepared" to urge York University to resume bargaining, but will still move ahead with back-to-work legislation to end the strike at Canada's third-largest university.

"We will assume our responsibility," McGuinty told the legislature.

"We will do everything we can to make sure that we get young people back in the classroom at the earliest possible opportunity."

The Canadian Union of Public Employees, which hasn't ruled out a court challenge of the back-to-work bill, blames the university for the deadlock.

Union officials called on the government Tuesday to give bargaining one more chance, saying if the premier throws his weight around an agreement can be reached before the bill is passed, eliminating the need for a court challenge.

The union said it made every effort to resolve the dispute -- even dropping its wage demands -- when a top provincial mediator was dispatched last week by McGuinty in a last-ditch effort to end the strike.

"Now is the moment. If ever there was a crunch, it was now," said Tyler Shipley, a spokesman for CUPE Local 3903.

"We want to go back to class. We want to go back to work."

The union's last offer was more than double the university's offer for settlement, York president Mamdouh Shoukri countered.

"That is an impasse by any standards," he said in a statement.

A government spokeswoman said McGuinty spoke with Shoukri and encouraged him to keep talking with the union, but York spokesman Alex Bilyk said late Tuesday afternoon there were no plans to restart negotiations.

Growing frustration over the protracted labour dispute spilled over into a confrontation with police during a union-organized march to the legislature.

Four people were arrested during the rally that repeated the call to restart negotiations. One person faces charges of assaulting a police officer.

"Negotiate, don't legislate," teaching assistant Noaman Ali chanted to the crowd of some 200 people.

Wayne Samuelson, president of the Ontario Federation of Labour, told the rally the government "should pass a law to send your employer back to the bargaining table so you can negotiate a collective agreement."

Lydie Brawer saw the protest from an office building across the street, threw on a coat, and went over to confront them.

"I want my kids to go back to school," said the mother of two York students -- one in fourth year who's in jeopardy of not graduating, and a son in first year who she said has "lost his appetite" for university.

"I sympathize with (the striking workers), but that's enough now. They have to think about the kids."

Some 75 people later broke off from the main rally and headed to the police station where the four arrested individuals were taken.

The crowd was confronted with barricades, some 25 police officers and nine officers on horseback before the peaceful demonstration dispersed after about 30 minutes.

The 12-week strike has also angered many York students, who fear their entire semester may be wasted if their teachers don't return to the classroom soon.

Pushing York University back to the table isn't going to help, said Catherine Divaris, who helped organize a coalition of fellow students who oppose the strike.

"They've been trying to negotiate for 12 weeks, I mean, what's the point?" she said.

"We're so close to getting back to class now, that would just be devastating. I think students ... would just lose complete faith in this entire process."

The coalition is organizing a students rally at the legislature Wednesday to demand action to end the strike.

McGuinty said the government will also look into establishing a commission that would determine when the studies of college or university students are in jeopardy due to a strike or lockout.

The premier recalled the legislature last weekend to introduce the back-to-work bill, hoping all parties would agree to pass it quickly.

The New Democrats oppose it, and have shot down every attempt to speed its passage in the legislature.

That means the legislation may not become law until Thursday, and students will have to wait until next week to return to class.

Some 50,000 students saw classes cancelled on Nov. 6 when 3,400 teaching assistants, contract faculty and graduate assistants walked off the job.

About 5,000 students were allowed back this week to attend courses taught by tenured professors.