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 spokeswoman 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 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.” —