British opposition leader David Cameron said this afternoon that he wants to forge a "big, open and comprehensive" power-sharing deal with the third-placed Liberal Democrats, after indecisive general elections.

"I want to make a big, open and comprehensive offer to the Liberal Democrats. I want us to work together in tackling our country's big and urgent problems," he said after Thursday's election resulted in a hung parliament.

Cameron indicated his terms for a possible deal shortly after Nick Clegg, leader of the potential kingmakers the Lib Dems, said the Conservatives had the "first right to seek to govern".

Labour Prime Minister Gordon Brown said he respected Clegg's view and the two opposition parties should "be entitled to take as much time as they feel necessary".

The Conservatives have won 302 seats, Labour 255 and the Liberal Democrats 56 with all but a handful of results in.

But Cameron's comments also highlighted how far the Conservatives and Liberal Democrats have to go in order to find common ground on key issues like Europe and defence.

The Lib Dems are europhiles, want to scrap Britain's Trident nuclear deterrent and favour an amnesty for illegal immigrants.

"I don't believe any government should give more powers to the EU, I don't believe any government can be weak or soft on the issue of immigration and the country's defences must be kept strong," Cameron said.

He also restated his backing for Britain's current voting system which the Lib Dems want changed, although he raised the possibility of an inquiry into this.

Cameron added it was "reasonable to expect the bulk of policies in our manifesto" would be implemented.

He highlighted common ground with the Liberal Democrats on lesser issues like civil liberties and the need for a low carbon economy.

"I think we have a strong basis for a strong government," he said.