Michael Phelps trains in Water Cube[CFP]

The battle for swimming golds was rehearsed in Beijing on Monday, with Olympic champions and world record holders testing water just four days before the Games start.

The Australian team, headed by captain Grant Hackett, were among the first to arrive. Hackett is seeking a third straight win in men's 1,500 meters freestyle at the Olympics. Teammate Libby Trickett, one of the world's best female sprinters, and women's 200 meters individual medley world record holder Stephanie Rice also had a brief training.

The Australian swimmers shared the pool with other big names including South Korean prodigy Park Tae Hwan, Dutch champion Pieter van den Hoogenband, French world record holder Alain Bernard, and Olympic champion Laure Manaudou.

American super star Michael Phelps, who has set eyes on winning eight golds in Beijing, was among the last few swimmers to arrive at the venue.

"It was the busiest day so far for the Water Cube, and everyone is excited to see all the stars, especially Phelps," said a venue coordinator Ma Xiaojun.

Phelps spent about 30 minutes training in the pool and declined to answer reporters' questions.