Games chief Jacques Rogge says bosses are "getting to grips" with the issue.

Empty seats were also seen at Wimbledon, the Basketball Arena, the volleyball at Earl's Court and the gymnastics at the O2.

While areas of seating where tickets have been sold to the public appear to be packed, at some venues "Olympic family" areas - often with the best views - have been emptier.

Mark Adams, the spokesman for International Olympic Committee chairman Jacques Rogge, said: "You have to allow for a small area of tickets and it is a small area of tickets and doesn't happen at all venues.

"The sport needs some tickets; the federation needs those for their officials to be in there. We give tickets to the athletes and their families, and journalists, as well, need some tickets."

"They need some flexibility and, unfortunately, that leads, sometimes, to those areas and those seats being empty but we are really getting to grips with this."