"We need collateral for Finland to be a part of the aid programme," the Finnish Finance Minister said of propping up Spanish banks.

In recent weeks Finland has reiterated that it can’t contribute to the Spanish bailout without collateral if aid is issued from a temporary crisis fund.

Parliament’s Grand Committee chair, Miapetra Kumpula-Natri, has also stressed the importance of collateral for Finland. She said on Tuesday that the collateral deal must be struck before the rescue package comes before Finland’s legislature.

According to Urpilainen, the Spanish rescue will take shape before the end of July.

The speaker of parliament, Eero Heinäluoma, told Yle via an adviser that parliament could be recalled quickly if needed.

On Monday night euro finance ministers agreed to offer Spain an initial 30 billion euros by the end of July. Last month Spain formally requested a banking rescue of up to 100 billion euros.