Finland can’t contribute to the Spanish bailout without collateral if aid is issued from a temporary crisis fund, according to Urpilainen. The Finance Minister said she expected bilateral talks with Spain to be long and difficult.
"We represent a tough line, and it’s the right thing to do because it protects the Finnish taxpayer from risk," she told Yle, adding that she was not sure whether other countries would also seek collateral from Spain.
Spanish officials on Wednesday said they were negotiating with the European Commission on the details of the rescue and hoped to present a figure for the amount needed when the Eurogroup meets on Monday.
In June Spain formally requested a banking rescue of up to 100 billion euros.
Last year Finland created a significant stumbling block for the eurozone's second rescue package for Greece, only agreeing to take part after striking a collateral deal with Athens in October 2011.