However he denied suggestions that the main factor behind the decision was worries over pollution in Beijing, an issue which he said had been "overstated".

"This is just standard operating procedure in Olympic games and not every athlete in every sport from every country participates in the opening ceremony," he said.

Athletes, Culbert said, "obviously wanted to be as prepared as they can possibly be", adding that there had been virtually unanimous support for Athletics Australia's decision.

The Australian team are expected to head for Beijing a couple of days before their competition starts, which is about a week after the opening ceremony.

Pollution concerns

China says it has spent $16bn over the past decade to improve the air quality in Beijing by shifting polluting factories out of the capital and raising car emissions standards, among other measures.

But Beijing's air quality remains a major concern for the International Olympic Committee (IOC) and some athletes.

Haile Gebresalassie, the world record holder in the marathon, has said he will not compete in the event at the Beijing Games because of the pollution.

Last year Jacques Rogge, the IOC chief, warned that unless there were major improvements in air quality, endurance events may be postponed or cancelled to protect competitors' health during the August 8-24 Games.

Hoping to avoid that embarrassment, Beijing plans to ban around half the city's three-million-plus cars from the roads during the games, while some factories will be closed down and construction work will be halted.

In a separate development on Tuesday the Olympic torch relay entered controversial territory as it moved into China's western region of Xinjiang.

Heavy security is in place to prevent protests by the region's ethnic Muslim majority.

The relay enters neighbouring Tibet later this week.