Mr Clegg's camp claim he is ahead in most of the country

A spokeswoman said a poll of 6,000 members showed 60.9% backed Mr Clegg, but there were "two big weeks to go".

But a spokeswoman for Mr Huhne said he was "catching up", with a "lot of undecideds" yet to cast a ballot.

The party says voting has been slower than at this stage in the last leadership contest, in 2006.

The 64,000 Lib Dem members have until Friday, 15 December to make a choice.

A party spokesman told the BBC that about 50% had so far cast their vote, compared with 70% at the same point in the last leadership election.

'Very positive'

The Clegg camp says it is ahead in all regions of the UK, except south-central England - which includes Mr Huhne's Eastleigh constituency - where it claims the two candidates are "neck and neck".

The Clegg team says it hase polled 8,000 Lib Dem members, with 60.9% of the 6,000 who responded saying they backed Mr Clegg, the MP for Sheffield Hallam.

Chris is showing that he's not only very good on policy, but also a very good communicator Chris Huhne campaign

A spokeswoman said: "We are very positive but we recognise there are two big weeks to go.

"As a result of that, Nick is trying to keep the momentum going... pushing towards the finishing tape."

A spokeswoman for Mr Huhne said he was doing "better than" polls suggested, adding: "There are a lot of undecideds."

'All to play for'

She also said: "We are running very close behind and catching up. The gap is narrowing.

"Chris is showing that he's not only very good on policy, but also a very good communicator.

"It was always said that Nick was the telegenic performer but I think that Chris has shown that he's good on policy and good on TV and in the media as a whole."

The spokeswoman added: "There's everything to play for."

A YouGov poll of 678 Lib Dem members for Sky News, carried out from 26 to 30 November and published on Saturday, suggested Mr Clegg was ahead with 56% of the vote among all those naming a candidate.

However, the results showed that Mr Huhne, on 44%, was still able to win, with 52% of members yet to cast a ballot.