London Transport officials warned shoppers they won't be allowed into the Westfield Stratford mall next to Olympic Park during the day on Friday and Saturday unless they are holding Olympic tickets or accreditation.
The decision was made because gigantic crowds are expected on both days as the games roll into high gear with the first track and field competitions at the Olympic Stadium, which holds 80,000 people.
Transport for London says the partial mall closures will be in effect from 10:30 a.m. until 5 p.m. on Friday and Saturday at Europe's largest mall, which has more than 260 shops, 70 restaurants and a 24-hour casino.
The glitzy mall has been extremely popular with Olympics fans, most of whom have to walk through the mall to get to the Olympic Park in east London.
Officials say the closure will not apply to people visiting hospitality venues.
Transport officials hope the closure will encourage visitors to see other parts of London, where some traditional attractions like theatres and museums have been reporting disappointing visitor flows since the games began.
"London has a rich and vast array of other attractions to offer during the games, so I encourage everyone to enjoy the theatres, restaurants, shops, free concerts, Live Sites and attractions," said London Transport Commissioner Paul Hendy.
Some 200,000 fans and workers are expected at the Olympic Park each day on Friday and Saturday, providing a stern test of security and crowd control procedures.
Jacqueline Scott, marketing director at the Westfield mall, said she expects shops to do well despite the closure to the general public.
"Crowd numbers will remain strong and traffic will continue to be busier than non-Olympic games trading days," she said.