One year after Dalton McGuinty's Ontario Liberals held onto power with a minority government, the premier admits the party's diminished numbers prevents him from keeping some election promises.

"You betcha," he said with a chuckle this week ahead of the one-year anniversary on Saturday.

McGuinty, who 12 months ago dubbed his victory "a major minority," said people needn't be impatient after a year.

"We'll take the time to deliver on our commitments over time," he said. "We've got to do it in a way that is respectful of our fiscal challenge."

The province is dealing with a $13-billion deficit.

McGuinty has yet to deliver on a promise to provide a tax credit for hiring immigrants. Finance Minister Dwight Duncan said he hasn't decided whether to put the tax credit in next spring's budget.

"We said in our campaign that you don't do all the things in one budget but that's still very much an important initiative," he said.

The Liberals also promised refunds on GO Trains that run late.

"The on-time guarantee is imminent," Transportation Minister Bob Chiarelli said. "We're very close to that announcement and that implementation."

The Liberals have made good on other campaign promises, including a 30 per cent rebate on undergraduate tuition and a home renovation tax credit for seniors.

Feud over power plants continues

Meanwhile, the partisan wrangling continues.

The Opposition is demanding McGuinty appear before a committee to testify about the Liberals' decision to cancel power plants in Oakville and Mississauga.

After twice refusing to testify at a committee about the scandal at troubled Ornge air ambulance service, McGuinty is strongly hinting he will not agree to testify about cancelling the gas plants either.

The Conservatives want McGuinty, his current and former energy ministers, and key Liberal strategists to face questions about the decision to cancel the gas plants, which cost taxpayers at least $230 million.

PC house leader Jim Wilson says they want top elected and unelected Liberals "to show up and stop the cover-up."

McGuinty says he supports the efforts of the committee to investigate the cancellation of the gas plants, which the opposition parties say cost closer to $640 million.

However, the premier says he disagrees with the move by the Tories and NDP to pursue what he calls a "vendetta" against Energy Minister Chris Bentley by trying to have him declared in contempt of Parliament.

With files from The Canadian Press