‘Aus athletes allowed to pull out of Olympics over smog’

Montgomery emphasised that he expected the country’s 433 team members would choose to compete but any decision not to would be respected.

“It is extremely unlikely an athlete will not compete, most athletes train for 10 years for this moment,” Montgomery said.

“For us, the athletes’ attitude to the event is paramount. If they don’t want to compete, that is fine. They will be under absolutely no pressure to compete if they feel uneasy or don’t want to compete.”

A haze of pollution has cut visibility across Beijing to a few hundred metres, jeopardising China’s promise of a “Green Games”.

Last week Beijing ordered more than a million of the city’s 3.3 million cars from the roads and closed dozens of polluting factories, apparently with little impact.

The state-run China Daily newspaper said this week that the government may ban 90 per cent of private cars and close more factories before the Games start on August 8.