The opposition on Thursday demanded a no-confidence vote against the government over a collateral deal with Spain made in exchange for Finland's support of an EU bailout for ailing Spanish banks.
"We do not accept wasting the Finnish taxpayers' money," said Timo Soini, who heads the populist and anti-EU Finns party, calling on parliament to reject the Spanish bailout.
Juha Sipilae, the chairman of the only other party in parliament in opposition, the formerly agrarian Centre Party, agreed.
"Support for the Spanish banks should be left to the Spanish banks' owners and the Spanish state, and not be placed on the shoulders of the Finnish taxpayers," Sipilae said.
Earlier this week, the government said Madrid had agreed to provide collateral to Finland in exchange for its participation the EU's 100-billion-euro ($122-billion) Spanish bank rescue.
Finland's share of the bailout amounts to about 1.9 billion euros, with collateral put at 763 million euros which will be paid in cash progressively.
Parliament met Thursday for the first time during a summer break since 1962 and was set to vote on the no-confidence motion and Finland's participation in the bailout Friday, when eurozone finance ministers are due to sign off on the rescue package.
Since Prime Minister Jyrki Katainen's broad coalition government enjoys a comfortable majority, both the collateral deal and Finland's participation in the bailout are likely to pass.
Finland, one of few EU countries to still enjoy a top triple-A credit rating, has long taken a tough line when it comes to eurozone bailouts -- first seeking collateral from Greece and now from Spain.
Soini rejected the argument that the collateral deals would limit the risk to Finland of helping bailout other eurozone states.
"The (government) parties have led the Fatherland first into a debt swamp and now into a bank swamp," he said.
Sipilae of the Centre Party demanded a referendum, claiming the government's decisions "require treaty changes and will result in a (European) federal state."
Finance Minister Jutta Urpilainen rejected the criticism, insisting that "we really are limiting our risks" with the collateral deals.