"All emergency and health services are facing a core funding squeeze in the current financial environment," members of the capital's London Assembly said in a report. "Funding for all of London's emergency and health services is one key unknown variable which may have an impact on their preparedness for the Games and ability to provide business as usual services," they added.

The government outlines steep public spending cuts next week as it attempts to tackle a record peacetime budget deficit. Emergency preparations have also been hit because bids for extra funds have been submitted without any clear picture of how many people will attend the Olympics and the following Paralympics, the report said.

London's fire brigade told the Assembly's Health and Public Services Committee it feared a 900,000 pound shortfall for its cover during the Games. Scotland Yard told the committee that police would be "very, very stretched" during what it described as its biggest peacetime operation.

The capital's ambulance services said it would need 300 extra staff. About 30,000 competitors and Olympic officials are expected to attend the 64 days of activity, but there will be no official estimate on visitor numbers until later this year.

At the same time as the Games, emergency services will also have to handle a WorldPride gay parade, the Notting Hill Carnival and celebrations for Queen Elizabeth's Diamond Jubilee.