Negotiators failed to reach agreement on leadership positions on the new Salo city council and municipal board, as well as for the city board itself.
The smaller parties represented in the negotiations, the Green League, True Finns, Left Alliance and Christian Democratic Party announced that they had formed a coalition to discuss the allocation of seats.
This development took the major parties by surprise - the Social Democratic Party, the National Coalition Party and the Centre Party.
The discussions continue on Monday evening. A resolution must be reached by next Monday, when the city's new council will convene its first official meeting.
The city of Salo merged with a number of other smaller municipalities to create a much larger township of over 50,000 residents.