IOC president Jacques Rogge said London 2012 was a "beautiful example" of what the Olympics should be about, with a Games that breathe life back into a tacky part of a host city.
The International Olympic Committee chief said the regeneration of the "polluted, derelict" quarter of east
London at the heart of the Games was a "remarkable" project.
The Belgian said he was confident London would be able to fix the IOC's concerns about transport problems, and insisted the new Olympic Stadium must remain as an athletics venue as 2012 chiefs work out what to do with it later.
"It's a beautiful example of city regeneration and I would say of a positive legacy," Rogge told news agencies in London, at the signing of a 10yr sponsorship deal between the IOC and US consumer goods giant Procter and Gamble.
"East London was totally polluted, derelict, and we are going to revive it. We are going to put back a heart, a soul,
life, housing and a local population. That's what's remarkable.
"They will revamp it with new access roads, building and social housing. That is a positive legacy of the Games.
"We always demand that there is a legacy which is not purely sporting, with one or two stadiums, but also has an
economic, urban and human legacy."
At the IOC's latest check up on London earlier this month, Olympic chiefs said they were happy with the progress
but said their chief concern was the British capital's congested road network.
"It's true that transport in London is difficult because there is lots of traffic but the roads are not very wide," Rogge said.
"But the organisers, along with the city and the public authorities, have come up with a transport plan which, in my
opinion, could work well. I'm not worried."