Waiting passengers at Stratford are now being told the Central Line will not re-open for at least an hour.
A fire alert means services are suspended on a key section of the line which serves the Olympic Park station.
TfL is advising Olympic spectators to use other Tube and main line services to reach Stratford, including the Underground's Jubilee line, the London Overground and the Docklands Light Railway.
One of the main Tube lines serving the Olympic Park was suspended as hundreds of thousands of people made their way to Olympic events
Tube trains to the Olympic Park suspended because of fire alert
PM on Olympic Transport