HELSINKI, Finland - Finnish voters have dealt a blow to Europe's plans to rescue Portugal and other debt-ridden economies, ousting the pro-bailout government and giving a major boost to a euroskeptic nationalist party.

With all ballots counted, the biggest vote-winner Sunday was the conservative National Coalition Party, part of the outgoing centre-right government and a strong advocate for European integration.

But its main ally, the Center Party led by Prime Minister Mari Kiviniemi, said it would drop out of the government after falling behind two opposition parties that have challenged eurozone bailouts.

The anti-immigration and staunchly euroskeptic True Finns don't see why Finland should rescue Europe's "squanderers," while the Social Democrats have called for changes to how they are funded.

The outcome means conservative leader Jyrki Katainen will have to invite at least one of them to coalition talks, raising questions about Finland's support for rescue packages that need unanimous approval in the 17-member eurozone.

"This result will give Europe grey hairs," political analyst Olavi Borg said. "It will cause them problems over the bailout funds."

If any single country pulls out, the system will crash, leading to a worsening of the debt crisis at a time when the group is deciding whether bailouts will end with Portugal or will also be needed for larger economies like Spain or Italy.

The conservatives won 20 per cent of the vote for 44 seats in the 200-member Parliament, two more than the Social Democrats. The True Finns, led by the plain-talking Timo Soini, soared from six to 39 seats. The results are preliminary and need to be confirmed by electoral committees by Wednesday.

"We can work with any party, as long as the election result and government program make it possible," said Katainen, the conservative leader.

Asked if he can strike a deal with the True Finns on aid to Portugal, Katainen said: "When responsible people sit at the table and discuss matters with Finland's interests at heart then solutions always will be found."

The sharp rise of the True Finns represents a watershed moment in Finnish politics, which have traditionally been dominated by the Social Democrats, Center and National Coalition parties.

"This is a historic change," Soini said as the votes were counted. The True Finns leader was also the biggest individual vote-winner in the election. He said his party would aim to enter government but conceded that coalition talks "could be quite difficult."

The biggest loser was Kiviniemi's Center Party, dropping 15 seats and a quarter of the support it had in the last election in 2007.

"It would appear to be a crushing defeat for us," the prime minister said, adding her party would go into opposition.

In a last-minute plea for voters to back parties that support bailouts, industrial organizations emphasized that the small, export-dependent economy would be threatened if the financial crisis in Europe spreads. The full, front-page advertisement in Finland's leading daily, Helsingin Sanomat, said that exports provide jobs for up to 1 million people and guarantee the country's well-being.

"The bailouts are a bit complicated and problematic for voters but there is really no alternative," said Mikko Partanen, 65, a retired businessman who voted for the conservatives.

Finland has pledged about C8 billion ($11.5 billion) in guarantees of a total C440 billion ($634 billion) in the eurozone's main bailout fund. But those likely will increase significantly as the currency union completes a promised boost of the fund's lending capacity.

"We are five-and-a-half million people," said Tuula Kuusinen, a True Finn candidate campaigning in Helsinki. "We have to stop giving money to every other country. We just can't afford it."