TORONTO - Ontario's minimum wage will rise to $10.25 an hour next spring as promised, Premier Dalton McGuinty said Monday, just three days after musing that he may put the brakes on the planned hike.

Issuing a rare mea culpa in the provincial legislature, McGuinty quickly backtracked from his earlier comments that he might not raise the hourly wage in 2010 as promised.

"It does call for some clarification on my part, and I take responsibility for muddying the waters," he said.

"Our commitment was to get to $10.25 an hour one year from now, and we will honour that commitment."

NDP Leader Andrea Horwath pounced on McGuinty's about-face and demanded to know whether he had finally made up his mind.

"While the premier is flip-flopping around and musing about this raise, people were worried. People were very concerned," she said.

"So now I need to ask the premier: Which premier are they supposed to believe? The premier that was musing a few days ago, or the premier that yet again made another promise today in this legislature?"

On Tuesday, the minimum wage will go up to $9.50 an hour from $8.75.

McGuinty was accused of shortchanging Ontario's poorest workers last Friday when he indicated the recession could prevent his government from hiking the hourly wage to $10.25 on March 31, 2010.

His surprise comments came just a day after his Liberal government tabled a budget that indicated it was on track to fulfil its promise to raise the minimum wage next year.

The budget also unveiled a plan to slash Ontario's corporate income tax rate to 10 per cent by 2013 and harmonize the provincial sales tax with the federal GST.

Opposition parties lambasted McGuinty for merging the two levies, calling it a tax grab because it will increase the cost of certain goods that were previously exempt from the provincial tax.

Both tax reforms marked a major detour for the Liberals, who had repeatedly dismissed calls from the federal Conservatives and business groups to implement the changes in order to attract more investment and turn around Ontario's economy.

Finance Minister Dwight Duncan defended McGuinty's minimum wage flip-flop as simply confirming the plans the government had outlined in last year's budget.

"That's the schedule that we originally laid out and the premier just reaffirmed that today," he said Monday.

McGuinty's sudden turnaround isn't that surprising, given that he's been "all over the map" on how to dig the province out of its economic troubles, said interim Progressive Conservative Leader Bob Runciman.

"Not too many months ago, he said it would be crazy to bring in new taxes in the midst of a recession," he said.

"When you make a commitment and then, a day later, you're suggesting that it's meaningless and that in fact it might not apply or take effect, I think that calls into question a whole series of issues surrounding his ability to occupy the office."

The premier's "irresponsible" actions also raise doubts about whether he plans to follow through on any of his promises, Horwath said.

"It seems to me that the premier doesn't know one day to the next what his plans are and what his plans aren't," she said.

"And that does not help the people of Ontario get a sense that their government knows what they're doing."