TORONTO - The Opposition stepped up its protest Monday against the Ontario government's plan to merge the eight per cent provincial sales tax with the five per cent goods and services tax, walking out of the legislature en masse.

Progressive Conservative Leader Tim Hudak tried in vain to get Premier Dalton McGuinty to agree to hold public hearings on the legislation to harmonize the GST and PST into a 13 per cent single sales tax, before leading the Tory exodus.

"We see a premier who ... won't listen to hard-working taxpayers and who has contempt for public hearings," Hudak told the legislature.

"Quite frankly, if he has that kind of contempt for taxpayers, I see no point in continuing with question period today."

Following Hudak's lead, each Opposition member walked across the aisle and presented McGuinty with a copy of one of his own, decade-old, quotes saying "public hearings; those two words go together nicely if you believe in true democracy."

Then each left the legislature, leaving the New Democrats and Liberal backbenchers to ask the rest of the questions for the day.

Last Thursday, three Progressive Conservatives were thrown out of the legislature after each called McGuinty a "liar," intentionally using unparliamentary language they knew would get them ejected from the house.

The New Democrats, who also oppose the HST and want public hearings on the issue, said Monday that the provincial Conservatives should convince their federal cousins in Ottawa not to pass legislation that would allow Ontario to harmonize its sales tax.

"If the Tories really want to do something productive they can go talk to Stephen Harper and tell him not to pass the enabling legislation in the federal House," NDP Leader Andrea Horwath said, referring to the Conservative prime minister.

"New Democrats believe it's extremely important to bring the voices of the people into this legislature and let the government know what the people are telling us about their concerns with the HST."

McGuinty later called the Tory walkout a "the wrong choice," saying the Opposition should stay in the legislature to ensure a healthy debate.

"Their responsibility in question period is to probe, provoke, cajole, highlight shortcoming in government policy ... and they should be there to do that," McGuinty said later Monday.

"I think it was a mistake on their part and we look forward to them returning to the house."

The federal Conservative government gave Ontario $4.3 billion to help convince the province to harmonize sales taxes, something Finance Minister Dwight Duncan calls "4.3 billion reasons" to create a single sales tax.

"It's ironic that they walked away from an hour-long opportunity to question the government, complaining that there's not enough opportunity to question the government," Duncan said after the Tories staged their walkout.

The Liberals also countered by releasing a series of quotes from Hudak and other Conservatives supporting tax harmonization.

Outside the house, Hudak acknowledged his party's opposition to the HST stands in stark contrast to the federal Conservatives, but said his job is to focus on the Ontario government's actions, not Ottawa's.

"My federal colleagues will make their own decisions," he said. "Our battle is to stop this massive sales tax grab here."

People across the province view the HST as a "greedy tax grab," and are encouraging his party to use every tactic it can to force public hearings, said Hudak.

"Outraged taxpayers are encouraging us to use any tools that we have at our disposal to make sure that we have public hearings on this bill," he said.

The government is expected to extend the fall session closer to Christmas to pass the HST legislation in time to deliver personal and corporate tax cuts meant to soften the impact of harmonization. Those cuts would kick in on Jan. 1, six months ahead of the HST.

British Columbia will also harmonize its PST with the GST on July 1, something Quebec, New Brunswick, Nova Scotia and Newfoundland and Labrador have already done.