Boris Johnson has said there is a "dispute" between City Hall and the government over who will foot the bill if the 2012 Olympics goes over budget.
London mayor Boris Johnson has clashed with his predecessor Ken Livingstone over the funding of the 2012 Olympics.
The London Mayor has said Londoners will "not pay a penny more".
Mr Johnson told BBC Radio 4's Today programme a deal signed by Mr Livingstone on cost over-runs was "far from clear" and he doubted it existed.
But he told BBC Radio 4's Today programme the terms of a deal on overspend struck by his predecessor Ken Livingstone were "far from clear".
Mr Livingstone said the comments were "bizarre" as the memorandum of understanding had been published.
A report commissioned by Mr Johnson says extra public cash will be needed for the Olympic Village and security.
He said it guaranteed Londoners would not pay if the games went over budget - a pledge since repeated by Mr Johnson.
In his report, David Ross, the Olympic watchdog appointed by Mr Johnson, revealed that "new economic and market conditions had put additional pressures on the venues' budget which had risen by £106m".
The report says the credit crunch, falling house prices, increased oil and raw material costs and the threat of terrorism as factors which will add "significant pressure" to the cost of the Olympics.
'Public funding'
Mr Ross also points to difficulties in securing finance for the Olympic Village and said work was ongoing with the developer, Lend Lease, and its banks to secure private equity and debt funding.
He warned: "In all scenarios some significant additional public sector funding is likely to be required to deliver the project."
However, he said savings made elsewhere meant there "has only been a very small increase in the overall anticipated final cost of the total programme of £16m."
Mr Johnson acknowledged there were "concerns" about over-runs on "big ticket items" but said that did not mean the project as a whole would go still further over budget.
He insisted savings were being made and said the key thing was to secure a "legacy" for London.
"The thing that's going to save London, all of us, loads of money in the long run, is if we can get this legacy right," he told Today.
'Not clear'
His Labour predecessor, Ken Livingstone, is understood to have signed a memorandum of understanding with the government allowing for any overspend to be covered by a combination of Lottery cash and London's council tax.
Asked if he would publish the document, Mr Johnson said: "I rather doubt that it exists.
These are going to be the most wonderful Olympics in history, since 753BC or whenever it was that they kicked off Boris JohnsonLondon mayor
"There is a doubt the agreement that was struck between the former mayor and the Labour prime minister about the exact extent of London's obligations."
The Department for Culture Media and Sport and Ken Livingstone both contacted the BBC after the interview was broadcast to confirm that the memorandum exists and is published on the department's website.
Pressed on the terms of the agreement in the Today interview, Mr Johnson said: "There is a dispute at the moment between the GLA and the mayoralty and the government about who is up for the over-runs in so far as they may or may not occur.
"The details of this deal are from clear."
He added: "What I want to do is to make sure there are no over-runs."
'Quality homes'
Mr Johnson, who is one of four Olympic Board members along with Olympics minister Tessa Jowell, London 2012 chairman Seb Coe and BOA chairman Colin Moynihan, pledged "real transparency" in the games' funding.
And he vowed to "make sure these Olympics are absolutely fantastic, which they are going to be, and for the long-term benefit of London and the rest of the country, which has so handsomely contributed".
He added: "These are going to be the most wonderful Olympics in history, since 753BC or whenever it was that they kicked off."
Speaking at Mayor's Question Time on Wednesday, Mr Johnson pledged new efforts to secure a legacy for Londoners.
He said: "We must also not lose sight that the Olympic Village offers the hope of new homes for many thousands of people.
"We cannot put that at risk by reducing the quality of these homes."
