British Prime Minister David Cameron faced a rebellion from within his own party today over a parliamentary vote next week on whether to hold a referendum on European Union membership.

Cameron, who publicly opposes any referendum, has moved the non-binding vote forward to Monday from next Thursday, when he will be in Australia for a Commonwealth summit.

But some "eurosceptic" lawmakers from his Conservative party have threatened to defy the expected use of a "three-line whip" -- the toughest disciplinary measure -- to get them to follow his official line.

Mark Pritchard, the secretary of the influential Conservative 1922 Committee of rank-and-file lawmakers, said he would defy any three-line-whip, under which MPs can be effectively expelled from the party.

"Ultimately this is about country first, party second and career last," Pritchard told BBC radio.

"This is fundamentally about freedom, about democracy and it's about the legitimacy of the European project."

Other lawmakers including ministerial aides have also reportedly signalled that they would do the same.

The motion calls for Britain to be given a three-way choice between remaining in the EU, leaving the 27-nation bloc or negotiating a looser relationship "based on trade and cooperation".

Cameron, who took charge of a coalition government with the Liberal Democrat party in May 2010, faces a growing groundswell from members of his centre-right party over Britain's involvement in Europe.

The parliamentary motion is not binding but if it is approved it will put Cameron under pressure to respect the will of lawmakers and go to the public for a referendum.

A parliamentary committee ordered the vote after more than 100,000 Britons signed a petition asking for a choice on the country's EU membership.

Britain last held a referendum on Europe in 1975 when a large majority of voters backed the country's continued membership in what was then the European Economic Community.