Londay's local city government said on Thursday that the city's transport infrastructure is still "one of the biggest risks" to the running of the 2012 Olympic Games.

Val Shawcross, chairman of the London Assembly transport committee, said that the city's aging transport network could struggle under the load of a predicted 5.3 million extra visitors during the Summer Games.

"In 2012 London is facing extreme demand placed on a network already creaking at the seams," Shawcross said in the report. "This is not just about spectators and visitors being able to get to and from events; Londoners will need to go about their everyday business too."

The report said that most of the 30 planned improvements to London's transport infrastructure have been completed or are on course for completion this year, but improvements to the London Underground Jubilee Line specified in London's original bid document are behind schedule.

It was oiginally expected to be completed in December 2009, but the city's transport body now predicts that it will have completed the work by June this year.

The assembly transport committee also said that about a third of London residents may need to change their route, time or mode of travel because of the extra congestion.

"Spectators and Londoners will also need to respond positively to 2012 travel advice," Shawcross said. "In the run up to previous games, host cities have often launched publicity campaigns to encourage people to change their travel habits.