Empty seats at too many venues is the International Olympic Committee's biggest complaint about the Beijing Games so far.

Gilbert Felli, the organisation's executive director, today said he was happy with almost every aspect of the first five days - apart from the low crowds.

He also revealed the IOC has received complaints from official sponsors that not enough people are visiting their specially prepared "showcase pavilions" in the Olympic Green area of the city.

Felli said: "We have had a fantastic opening ceremony and I am pleased with the village, the food, the transport and the smooth running of the sport so far.

"But one area which does not merit as much praise concerns the issue of spectators in some of the venues.

"I would like to see all stadiums full but if you compare to past Games this is not the worst.

"It is down to the structure of some of the sports and the fact, in the early rounds, people only come for part of the day."

The Chinese organisers, BOCOG, are also concerned about the spectator issue and have been using volunteers to fill the empty seats.

To appease the sponsors, they also plan to ease the tight restrictions on access to the Olympic Green.