"I say to boards, don’t tell me it can’t be done," McGuinty said after touring a school in Waterloo.
"The Toronto District Catholic Board, one of the biggest in the country, got it done, so I know we can get it done in this community just as we can in other communities right around the province."
The Liberal government sent out letters Friday to every school trustee in the province urging them to get the contracts signed.
The government is threatening legislation if boards and teachers don't sign new agreements by Sept. 1, when the old contracts would automatically roll over and give teachers raises of up to 5.5 per cent.
The province is fighting a $15-billion deficit and can't afford a pay hike for teachers, said McGuinty.
"Let's recognize that, let's accept that, let's do it in a way that preserves the gains we have made in education," he said.
The Toronto District Catholic Board is the only one in the province to sign a deal with their teachers based on a provincial agreement with the Ontario English Catholic Teachers' Association.
That agreement, which McGuinty calls a "road map" for boards, allows over one-third of younger teachers to move up the salary grid and forces teachers to take three unpaid days off in the second year.
The union representing Francophone teachers has accepted a very similar deal, but no local agreements have been signed.
"The door is open, the welcome mat has been laid down and we're inviting school boards and teachers to what I believe they know in their heart of hearts must be done," said McGuinty.
Linda Fabi, director of education at the Waterloo Region District School Board, worried legislation would anger the unions and damage relations between teachers, boards and the government.
"It’s absolutely critical at the end of this that schools and politicians and educational leaders are able to work in collaboration," Fabi said.
"So it’s important that we don’t destroy our relationships in the middle of all this."
The Progressive Conservatives support a public sector wage freeze but say the OECTA deal allows many teachers to get raises and would cost an extra $300 million if accepted by all teachers.
The Tories complained they haven't heard from McGuinty about recalling the legislature to impose a contract on teachers, even though the premier admitted he'd need the support of at least one opposition party to pass the bill.
It's up to them to contact him, said McGuinty.
"I hope that at some point in time they’ll pick up the phone and give me a call," he said.
"I’m not sure why they are sitting on their hands. I think I’ve been in the media several times over now talking about our plan."
The NDP are "absolutely terrified" of any measure that would freeze wages in the public sector, he added.
McGuinty refused to say if any legislation to impose a deal on teachers would be a confidence motion, meaning its defeat would automatically trigger an election.
It's clear McGuinty is trying to make the school boards the scapegoat in his labour battle with teachers, said Deputy PC Leader Christine Elliott.
"They are blaming the boards," she said. "They have no one really to blame but themselves."
The New Democrats said the Liberals should be trying much harder to reach negotiated settlements with teachers.
"The government is dead set on moving forward with legislation that we know is not in the best interests of the province," said Catherine Fife, the NDP candidate in the Sept. 6 byelection in Kitchener-Waterloo.
"The premier has passed on the problem to school boards, boards whose hands are tied by the budget."
McGuinty said he was confident any legislation imposing a contract on all teachers would stand up to a court challenge, something he warned the legislated wage freeze the Tories propose for all public sector workers would not.
"We started back in February and we're trying to demonstrate to everybody — but especially to our teaching partners — that we have a sincere interest in reaching out," he said.
"If worse was to come to worse and we were to end up in court, for example, we want to demonstrate to the judges that we have in fact been earnest in our efforts to reach out."