TORONTO -- Premier Kathleen Wynne's Liberals suffered a crushing defeat in two Ontario byelections Thursday, but vowed the losses would not be repeated in the general election, expected as early as this spring.

The general election will be "the real decision point" for voters, said Wynne as she urged Liberals not to read too much into the opposition parties' victories in Niagara Falls and Thornhill, north of Toronto.

"Whatever has happened in these byelections tonight is not reflective of what's going to happen in the general election," she said. "We cannot extrapolate from tonight. That is not the way it will go."

The New Democrats took Niagara Falls from the Liberals, who had held it for the past decade, while the Progressive Conservatives held Thornhill.

The results don't change the status of the minority Liberal government, but the byelections were viewed as crucial tests of voter intentions, and party messages, in advance of a general election.

New Democrat Wayne Gates, a Niagara Falls city councillor, defeated former Progressive Conservative MPP Bart Maves in a hard fought battle while the governing Liberals came in a distant third.

NDP Leader Andrea Horwath offered no hints about her future plans regarding an election as she spoke at Gates's victory party, saying voters are clearly fed up with the Liberals and feel it's time for a change in government.

"We can show them the respect they deserve, respect the value of the money that they send to Queen's Park and stop the waste and the scandals," said Horwath. "That's the change that we need in Ontario."

Despite a strong challenge from the Liberals in Thornhill, optometrist Gila Martow managed to hang on to the riding for the Progressive Conservatives in what many considered a must-win situation for Leader Tim Hudak.

Both ridings are held by the Conservatives federally.

Wynne, who had downplayed Liberal expectations ahead of the byelections, admitted her disappointment at the outcomes.

"This is a hard night," said Wynne. "We're not going to pretend that it's not a hard night for everyone who has worked so hard, not going to pretend that it is not a hard night in Niagara Falls."

A fired-up Hudak didn't admit any disappointment at seeing the NDP take Niagara Falls, and said the Conservatives captured the most votes of any party "by far" when ballots in both ridings were counted.

"This evening's results prove that the people of this province want change," Hudak said in Thornhill. "They sent the McGuinty-Wynne Liberals a clear message (that) they want leadership that will take decisive action, implement a plan to balance the budget and create jobs."

Wynne downplayed Liberal chances ahead of the votes, calling byelections "unique creatures" that allow people to safely lodge a protest against the government knowing she'd still be premier Friday morning and leading a minority Liberal government.

Losing Niagara Falls to the NDP is a major disappointment for the Conservatives, but is unlikely to change Hudak's demands for a general election as soon as possible.

The big question is will the NDP win be enough to convince Horwath to stop propping up the minority Liberal government and trigger an election, or will she seek a third budget deal with Wynne.

The premier had said she doesn't plan to call a spring election, and had promised to stick to her plan to introduce a budget even if the Liberals had won both byelections.

Wynne campaigned hard ahead of Thursday's vote, including a four-day, 12-city tour with stops in both ridings, as well as announcing $100 million in spending in Niagara Falls and promising a new hospital in the region.

The Liberals were blamed for the closing of the Fort Erie Race Track after they cut slot machine revenues to horse racing, but last week it was announced there would be a 2014 race season at the track. Fort Erie is Tim Hudak's home town, and the track was one of the largest employers in the Niagara Falls riding.

The Ontario Federation of Labour said Hudak should be embarrassed by his party's loss in Niagara Falls, and realize that the Conservatives union-bashing tactics are not playing with voters.

"His anti-worker, anti-union message is clearly not resonating in his own back yard... and this has got to be a tremendously embarrassing situation for the leader of the Opposition," said OFL president Sid Ryan.