Australia's swimming trials unearthed an impressive crop of young talent raising hopes the country might regain its superpower status in the pool, but this year's London Olympics could just come too soon to harvest a golden haul.

Australia won six swimming golds at Beijing, following a seven-gold haul at Athens in 2004 and five at the Sydney 2000 Games to finish runner-up to the United States in the medal standings at the past three Olympics.

But the country of five-time Olympic champion Ian Thorpe, who flopped at the trials on his comeback, and retired 1,500 meters great Grant Hackett, has tumbled down the world rankings.

Australia managed only two titles at last year's world championships in Shanghai, finishing seventh in the medal table.

"The gap's closed on us by the nations that have finished third and down," Australia head coach Leigh Nugent said at the close of the Adelaide trials on Thursday, pointing to China and France as big improvers.

Despite flickers of hope emerging in other events, the burden of Australia's Olympic hopes lie squarely on the shoulders of their reigning world champions - James Magnussen and his 100m freestyle relay teammates.

Magnussen's stunning 47.10 sec swim to clinch the 100 freestyle title in Adelaide underlined his favorite status to secure gold in the event at London.

The swimmer's formidable understudies all qualified under the Olympic A standard in the final, meaning the relay team will be hard to beat.

The 20-year-old Magnussen, nicknamed "the Missile", also surprised himmself and probably many of his rivals by swimming the second fastest 50 freestyle over the past year behind Brazilian Olympic and world champion Cesar Cielo.

Nugent said Australia's 44-member squad named on Thursday could realistically hope for about 15 medals in London, the same amount won in Athens.

Beyond Magnussen and the relay team, finding genuine gold medal chances among them is a tougher task.

Twenty-year-old Thomas Fraser-Holmes put down a marker with impressive wins in the 200 free and 400 IM, while Leiston Pickett, also 20, showed herself to be a medal candidate in the 100 breaststroke.

The youth-led assault at the trials put paid to the Olympic ambitions of former world champions Thorpe, Michael Klim and Geoff Huegill, but Australia's old guard may yet prove to be the team's best hopes of cobbling an extra gold or two.

Stephanie Rice will defend her 200 and 400 individual medley titles at London after brilliant comeback swims following shoulder surgery in December to qualify for each at the trials.

Reuters in Melbourne