Australia's multiple Olympic champion Ian Thorpe has removed another hurdle in his bid to return to competitive swimming by finally tipping the scales at under 100 kilos, local media reported on Thursday.

The five-times Olympic gold medallist's weight had ballooned since retiring from the pool in 2006 but punishing altitude training in Switzerland appears to have paid off.

Thorpe's manager Dave Flaskas said the Abu Dhabi-based Australian great could race at the New South Wales State meet next February after what is expected to be his comeback in Singapore on Nov. 4.

"He is back to his race weight, which is just under 100kg," Flaskas told the Courier-Mail.

"He is thriving overseas and is training really hard under [coach] Gennadi Touretski - both in the water and on dry land.

"It's clear this is not a half-baked comeback. He is really serious," added Flaskas on the subject of the November World Cup event.

Flaskas also scoffed at speculation that Thorpe had undergone plastic surgery after looking trim and square-jawed at the royal wedding in London last weekend.

"No, he doesn't have time for anything like that," said Flaskas. "He has dropped an awful lot of weight and it's clear in his face.

"He is also super happy and really believes that his best swimming is ahead of him - particularly in the shorter, sprint events."

The 28-year-old Thorpe, widely regarded as Australia's greatest swimmer, has also consulted with old rivals Alex Popov and Pieter van den Hoogenband as part of his preparations for the 2012 London Olympics.