London’s Olympic Stadium will welcome the athletics events later in the day, ensuring the Olympic Park’s busiest day since the Games opened a week ago.
More than 200,000 people will be at the park, prompting warnings for those not attending the Games to avoid the area.
The Central Line, which serves the Olympic Park in Stratford, is suspended from Liverpool Street to Leytonstone.
It follows a signal failure at Bethnal Green station, London Underground said. Tickets are being accepted on National Rail services in the area.
Friday’s events at the 80,000-capacity Olympic stadium will bring thousands more people pouring into the east London park and mean access to the neighboring Westfield shopping centre will be restricted for the next two days.
Only staff and Olympic ticket holders will be able to go into the centre between 10:30 BST and 17:00 as organizers seek to minimize congestion.
Transport for London (TFL) said public transport services and roads to the Olympic Park would be exceptionally busy on Friday and urged anyone not going to the site to avoid the area.
The Docklands Light Railway, Jubilee and Central lines are expected to be busier than usual, especially in the morning, evening and late-evening peaks and driving in central London should be avoided where possible, TFL said.
London’s transport commissioner Peter Hendy said: “This Friday and Saturday will be the busiest days of the Games so far as the Olympic Stadium opens its doors and sporting events continue to take place across the capital.
“Westfield Stratford City may not be open to shoppers without a ticket during these times but London has a rich and vast array of other attractions to offer during the Games.”