By Jussi Rosendahl and Terhi Kinnunen
HELSINKI (Reuters) - Finnish voters threw sand in the gears of European Union plans to bail out Portugal on Sunday by thrusting the anti-euro True Finns party into a leading role in parliament.
Finland's parliament, unlike others in the euro zone, has the right to vote on EU requests for bailout funds, meaning it could hold up costly plans to shore up Portugal and bring stability to debt markets.
The strong showing for the True Finns reflects growing public frustration in some EU states with stronger economies, notably Germany, at having to foot the bill to bail out the weaker economies such as Greece, Ireland and Portugal.
Though the center-right National Coalition party was set narrowly to win the Finnish vote, according to a forecast from broadcaster YLE, the anti-euro True Finns are set to be one of the four top parties in parliament and are therefore likely to be involved in talks on forming a government.
Charismatic True Finns leader Timo Soini said he wanted to change the terms of the bailout for Portugal.
"The package that is there. I do not believe it will remain," Soini said on YLE, referring to the rescue package being worked on for Portugal, the third euro zone country to need a financial rescue after Greece and Ireland.
He later told Reuters his aim was for Finland to "pay less to Brussels." "It is a bad deal," he said of the Portugal plan.
With 93 percent of votes counted, the True Finns were one of the top four parties at about 19 percent of the vote, more than four times their result in the last election in 2007.
Broadcaster YLE forecast the True Finns would take third place and win 39 seats. Soini said the party would at least "get an invitation to talks" on a new government, which is expected to be formed in mid-to-late May.
YLE forecast the center-right National Coalition would be the actual winner of the vote, with 43 seats, and the main opposition Social Democrat Party would be second with 42. The current biggest ruling party, the Center Party, would win 35.
Any of the winning parties will need to form a coalition to get a majority in the 200-seat parliament and analysts expected the talks to be difficult.
With the National Coalition set to come first, 39-year-old Jyrki Katainen, the finance minister of the outgoing coalition, was set to become prime minister and have the job of forming a government.
He played down the idea that Finland would now join the euro zone's awkward squad.
"Finland has always been a responsible problem solver, not causing problems. This is about a common European cause," he said on television.
"After the elections, the biggest parties will begin to look for common ground."
(Additional reporting by John Acher, Writing by Ritsuko Ando, Editing by Jon Hemming)