London - Olympics organisers said on Monday they were forced to check the welding on 200 000 temporary seats across venues after fans complained that seats at the rowing and archery collapsed under them.
Many of the London 2012 competition venues use temporary stands, including those for the hockey, basketball, swimming, water polo, equestrian, beach volleyball, shooting and triathlon.
Local organisers LOCOG said the welding had given way on one or two seats.
"In Eton Dorney [the rowing venue] and at Lord's [the archery venue], it wasn't 'the seating', it was one seat, so the welding of one seat came away," said London 2012 spokesperson Jackie Brock-Doyle.
"Overnight they have gone through all the seating that this particular contractor has put in place, to have a look across the whole Games.
"And the issue of the welding seems to be in two seats. They haven't found an issue with anything else. They haven't had a problem.
"It is the spot welding on two of the seats. There are about 200 000 temporary seats. It just means that the seat falls slightly forward."
Fewer than 100 had to be replaced following the check.
The rowing is taking place at Eton Dorney lake, west of London, while the archery competition is being staged at Lord's cricket ground in northwest London, where temporary stands have been erected on the pitch.