Stumping up more cash to fill a post-Brexit €15 billion ($25b) black hole in the EU's budget would be "unbearable" for Finland, its Europe minister has said, as divides opened up on the continent as to how the bloc's spending should be reformed.
Sampo Terho said it was crucial that the EU cut its budget rather than rely on members to pay more.
"When the EU becomes smaller, the budget should become smaller. That's all there is to it. That's the logic we abide by," Terho told the Daily Telegraph in Helsinki.
As the UK is the third largest net contributor to the EU budget, officials in Brussels are scrambling to figure out how to cover an annual shortfall of around €12b-15b when the country leaves the bloc.
"If that gap were to be filled with other countries' payments, I see that as an unbearable solution. We must cut the budget."
Finland, which counts the UK as a key trade and defence partner, is a net contributor to the EU budget - meaning it pays in more money to the bloc than it receives.
Terho added that Finland would push for a Brexit deal that allowed trade to be as "smooth as possible" and hoped the UK would continue to be a "close friend" in defence and security.
He also warned, in a swipe at Emmanuel Macron, the French president, that seizing Brexit as an opportunity to push forward an agenda of deeper integration across member states was "absolutely the wrong conclusion".
Budget reform is poised to be one of the most controversial results of Brexit, with members and senior EU officials split as to how the funding gap should be covered.
If that gap were to be filled with other countries' payments, I see that as an unbearable solution. We must cut the budget.
Germany is likely to face the biggest budget rise, estimated at €3.8b, while France could see its share of the cost rise by €1.2b.
Macron has suggested introducing tax rises as one way of keeping money flowing from Brussels to the EU's less wealthy member states.
Meanwhile, Jean-Claude Juncker, the president of the European Commission, has said that "what we need has to stay, has to be funded".
However, Finland is strongly opposed to any arrangement that requires it to cough up more.
"Finland is very firm that we don't want to see our costs go up and whatever tools we can apply in achieving this goal are something to think about it," Terho said.