Updated

By Nick Mulvenney

SYDNEY (Reuters) - World class displays from a string of youngsters at the Australian swimming championships have shown returning champions like Ian Thorpe they will have a fight on their hands for places at the London 2012 Olympics.

Thorpe, who announced his comeback in February, and Libby Trickett, who came out of retirement last year, were not eligible for the eight-day event, which doubled as the trials for July's world championships in Shanghai and ended on Friday.

A confident Magnussen said five-times Olympic champion Thorpe and former world champion Michael Klim, who also announced his return from retirement this year, would not have it all their way in the blue riband sprint.

"A lot of the press has been about us younger guys having to chase Thorpey and Klimmy when really it's the other way round, they're going to be chasing us," he told reporters.

"At the age we're at now, we're improving rapidly each year so I can't see any reason why we won't improve again on that next year."

"They are not being sarcastic or belittling each other. It's 'if you want to beat me then you better get in here and have a crack because it's not going to be easy'," he said.

"FLAB TO FAB"

The 23-year-old acknowledged that Trickett had been much quicker in the freestyle before her short retirement but looked forward to challenging the multiple world and Olympic champion.

"Certainly if she can get back to where she was I'd like to have her to chase, a bit of cat and mouse, it'll definitely be good," said Coutts.

"Obviously there'll be a lot more hard work to come but I'm really happy with how I've done and hopefully for Shanghai I can go faster."

Among them was former world champion Geoff "Skippy" Huegill, whose "flab to fab" comeback helped inspired Thorpe's return.

Olympic relay gold medalist Emily Seebohm, who had been suffering from swine 'flu, made the team despite collapsing after finishing second in the 100m backstroke final on Sunday.

(Editing by Mark Meadows)