Poland, Hungary, Slovakia and the Czech Republic said today they would reject any British demand to change European Union laws that would lead to discrimination of their citizens or limit their freedom of movement.

British Prime Minister David Cameron is seeking to renegotiate the terms of Britain's relationship with the EU ahead of a referendum by the end of 2017. He has pledged to try to win back some control over the number of people coming to Britain amid voter concerns about the strain on public services.

Cameron has said he wants to limit EU migrants' access to welfare payments, and to have the power to remove them if they are unable to find work within six months.

"We can support those elements of UK reform proposals with a potential to modernise the European Union, especially as concerns increasing competitiveness and a stronger role of national parliaments," the four countries, called the Visegrad group, said in a statement.

"However, as the Visegrad Group countries consider the freedom of movement one of the fundamental values of the European Union, proposals regarding this area remain the most sensitive issue for us. In this respect, we will not support any solutions which would be discriminatory or limit free movement," they said.

EU officials have highlighted Britain's demands on immigration as the most problematic in the renegotiation, warning that they jar with basic EU treaty law barring discrimination against EU citizens on national grounds.