Hackett, who will be a TV commentator when the London Games begin on July 27, believes Magnussen is the one to beat in the two-lap sprint, but says Targett is a big improver who will push the world champion all the way.

“There’s no such thing as a certain gold medal but James is a phenomenal athlete who is thriving in the limelight,” Hackett said at the launch of the Nine Network’s Olympic Games broadcast in Sydney on Wednesday.

“However, Matt Targett is pushing him all the way.

“It’s a big call but we have the potential to win gold and silver in that event in London.”

Hackett, who won 1500m gold at the Sydney and Athens Games before taking the silver in Beijing, also praised the comeback efforts of Ian Thorpe.

He said Australia’s greatest Olympic swimmer could still make the team for London at next week’s national titles but it was more likely to be in the longer 4x200m freestyle relay than the 4x100m.

“He’s built for that race (200m) but I don’t think the 100m is his event,” he said.

“Ian has brought a lot back to the sport and what he’s achieved so far is unbelievable but he still has a lot of work to do.”

Hackett also said Australia’s women could surprise in London with the versatile Alicia Coutts leading the way with Emily Seebohm another to watch closely.

And he said three-time gold medal winner in Beijing Stephanie Rice could prove she was an enduring champion if she could win another gold in London.

“That’s the test of a true champion, to come back and win again four years later,” he said.