British cycling has signed its own sponsorship deals
The government has rejected claims it will not be able to raise enough cash from private firms to fund Britain's 2012 Olympic athletes.
Olympics Minister Tessa Jowell has said she is "confident" the £79m needed to plug a funding gap will be found.
But there are fears the credit crunch and more attractive sponsorship options - such as backing individual athletes - will deter many firms.
And one sponsorship consultant dubbed the government's plans "confused".
In Beijing on Friday, Gordon Brown said he would hold a Downing Street summit in the autumn, involving all the major sports governing bodies, to look at lessons that could be learned from Beijing.
It will include incentive plans to raise at least £80m in private sector sponsorship for 2012.
He said he was keen to capitalise on the enthusiasm generated by British success in Beijing to bring private sponsors on board: "This is the time for them to now make their decisions. They can see the people who have done well, they can see the people who might do well for the future."
The government has pledged £600m to fund training in the run-up to the London Games - with most of the cash coming from the National Lottery.
It had originally said that £100m of that would come from private firms - but that was reduced to £79m when more lottery cash became available.
The government this week launched a sponsorship drive, Medal Hopes, aimed at plugging the funding shortfall.
The plan is to sell access to British athletes as they prepare for the 2012 Olympics to local, regional and national sponsors.
It may also include the sale of post-Games naming rights to new venues being constructed, including the main stadium.
But Tim Crow, of sponsorship consultants Synergy, which represents several major Olympic backers, questioned whether it could raise the cash needed.
"There are some quite big question marks around whether this scheme offers good value to sponsors and whether it is going to be able to raise the £79m," he told the BBC News website.
He said it may be difficult to sell the naming rights to the Olympic stadium in the years leading up to the games, given that the rights would not become available until after the event in 2013.
And potential sponsors were not clear on how Medal Hopes fitted in with existing 2012 sponsorship schemes.
They also already had the option to sponsor individual teams, such as the cycling or rowing teams, or even individual athletes, which could prove more attractive.
"However well intentioned it is, [Medal Hopes] is already causing a lot of confusion," he added.
But Olympics minister Tessa Jowell, has insisted that the organisers of the London Olympics are on course to meet their sponsorship target.
She told BBC Radio 4's Today programme: "The staging of the Games is very heavily dependent on sponsorship and London 2012 are further ahead than any other city has ever been, at this stage, in raising sponsorship from major private companies to support the staging of the Games.
"I've had the opportunity to meet with a lot of British businesses in the three weeks I've been in Beijing, and I am confident that this is a soundly based ambition that we can raise this money.
"We have announced our intention to do so - let's come back in 18 months' time and review progress."
President of the International Olympic Committee Jacques Rogge has, meanwhile, told the BBC that he is not surprised Team GB has done so well at the Beijing Games.
Mr Rogge said Britain had been right to target certain sports - and to give them lottery funding.
"I knew, frankly, that there would be probably more than 13, 14, 15 medals - you've won 17 gold medals to now.
"It doesn't surprise me because I know what you've put in place. You've put a very good effort.
"You have targeted special sports, you have targeted some sports where you could win more medals, which was very wise because you have a population of 60 million - you cannot compete with these mammoths like the United States or China.
"You had a lot of lottery funding - it's been criticised, but the results are there, and I think it was worthwhile."