LONDON (AFP) - British Prime Minister David Cameron on Monday brushed off an EU payment demand despite the European Commission's warning that Britain faces fines if it does not pay up by December 1.

"Britain will not be paying two billion euros (S$3.24 billion) to anyone on December 1 and we reject this scale of payment. We will be challenging this in every way possible," he told parliament.

"The scale and timing of this demand is unacceptable," he said, earning cheers from members of his Conservative Party.

"It is British taxpayers' money, it is not small change."

The interim EU budget commissioner, Jacek Dominik, on Monday said Britain must contribute an extra 2.1 billion euros to the European Union budget or face fines.

But Cameron responded by saying: "There is no pressing need for the money to be paid." He explained that the EU figure was a provisional estimate that would not be definite until next year.

Cameron, facing a rising tide of eurosceptic voters deserting him for the UK Independence Party, has promised an in-out EU referendum in 2017 if he wins elections next year, making the latest exchanges with Brussels even more high-stakes.