* Minister sure True Finns will not block Portugal bailout
* True Finn candidate says party to remain opposed to plan
* Social Democrats open to negotiation (Adds comments from SDP party secretary, analyst)
By Ritsuko Ando
HELSINKI, April 15 Finland's National Coalition, the party tipped to win elections on Sunday, said it was confident the next government will support an EU bailout plan for Portugal, but an anti-euro opposition party remains against it.
The possibility that the populist True Finns party may join a new coalition has raised the risk that the next government could block the bailout for Portugal, which is negotiating a rescue with the EU and IMF expected to total 80 billion euros.
Finland, unlike other euro zone countries, retains the right to put requests for funds to a vote in parliament.
Senior National Coalition member Jan Vapaavuori said the True Finns and opposition Social Democrats, who support the EU but are critical of financial rescues, may agree to support a bailout vote or at least abstain as a condition of joining the government.
"I have full confidence that Finland will not cause any problems concerning the support package for Portugal in the future," Vapaavuori, who is housing minister in the outgoing government, told reporters on Friday.
But True Finns candidate Simon Elo told Reuters the party would not change its views or agree to an abstention in the parliamentary vote in order to gain seats in government.
"We would lose our face in front of all of our voters. It's something we cannot do," he said. "I have a firm conviction that we shouldn't have this kind of package policy in the European Union."
A poll by public broadcaster YLE on Thursday showed the right-leaning National Coalition leading with 21 percent support, closely followed by the Centre Party, Social Democrats and True Finns, each with around 15 to 19 percent.
Finland's current government is a four-way coalition of the National Coalition, Centre Party and two smaller partners, the Green Party and Swedish People's Party of Finland.
Analysts say that assuming the National Coalition wins the most votes on Sunday, it is likely to form an alliance with other parties to ensure a majority in parliament.
Vapaavuori said the party was open to working with the True Finns as long as they could agree on a government programme.
"In order to gain a place in the next government, of course the True Finns have to agree on a programme which is more pro-European than anti-European," he said.
"Either it's a pre-condition for them to support Portugal in the next government, or at least not to vote against it ... I'm sure that Finland will be in line with other European countries in the next government," Vapaavuori said.
Support for the True Finns, led by charismatic leader Timo Soini and which had only six seats in the outgoing parliament, has nearly quadrupled since the 2007 election.
Analysts say the party has harvested popular anger over issues ranging from bailouts of debt-laden European states to immigration and unemployment.
Kimmo Gronlund, a research director at Abo University, said Soini was likely to tone down his rhetoric on the EU if that could get him into government.
"Although he seems very strict with what he says, it's clear that Soini will find a way to explain to his people why the party would need to compromise," he said. "It would be strange for a party to grow so much but not want to use that power and enter government."
Vapaavuori said it would be even easier to reach some kind of agreement with the Social Democrats, although the party wants private investors to shoulder more of the risk.
Mikael Jungner, a party secretary for the Social Democratic party, said the party was open to negotiation and still supported Finland's role in the EU.
"We think that this crisis has to be managed and we think that we can help Portugal. But there is this one condition that we have. It's the need to get private investors to take part in this bailout," he said. (Additional reporting by Jussi Rosendahl, Editing by David Stamp)