Finnish Prime Minister Matti Vanhanen is to fly to the Polish capital Warsaw in an attempt to defuse a confrontation over the EU's relationship with Russia.
The EU is keen to improve energy co-operation with Russia
Poland is currently blocking the start of EU-Russia negotiations on a new strategic partnership agreement.
Warsaw has said before that the EU should be tougher with Russia, and it is now digging in, just a week before talks on the pact were due to start.
It wants a Russian ban on Polish meat and vegetable imports lifted first.
It also wants Russia to ratify an international agreement on energy investment and distribution.
BBC Europe correspondent Jonny Dymond says Poland is quite badly isolated within the EU on this question.
Only Lithuania fully supports its position.
Other countries, though they agree that Poland has a case, are frustrated with Poland's robust negotiating style, our correspondent says.
Mr Vanhanen has the role of attempting to persuade the Poles to back down because his country currently holds the EU's rotating presidency.
An EU-Russia summit is scheduled for 24 November, and the EU would like the negotiations on the new agreement with Russia to begin then.