LONDON - Michael Phelps will put the final gloss on a glittering Olympic career at the London Games, but he's not the only star set to shine when competition begins Saturday at the Aquatics Centre.

Phelps's unprecedented eight gold medals at the Beijing Games led the United States to a 31-medal haul in 2008, including 12 golds from the 32 events, nine silver and 10 bronze.

Phelps won't try to match that feat, but his seven-event program gives him plenty of room to make more Games history and anchor a US team out to continue its dominance against traditional rival Australia and rising powers such as China.

Phelps is the two-time defending champion in all four of his individual events -- the 100m and 200m butterfly and 200m and 400m individual medley.

No male swimmer has won the same Olympic event at three successive Games, giving Phelps another milestone to aim for.

Japan's Kosuke Kitajima is also eyeing a golden treble after winning back-to-back 100-200m breaststroke doubles in 2004 and 2008.

One of Phelps's biggest challengers figures to be team-mate Ryan Lochte, who has emerged as a serious threat in both medleys.

But Phelps says they can't afford to overlook anyone.

"Ryan and I aren't here just racing each other," he said. "We're racing the whole world."

Adds US men's head coach Gregg Troy: "It's a pretty big world."

"There's a lot of good swimmers out there. I think if we take anything

lightly we're making mistakes."

Australia is bringing in the big artillery with James "The Missile" Magnussen and James "The Rocket" Roberts, in the prestigious 100m freestyle.

Magnussen is the 100m free world champion and the fastest man ever in a textile suit with a 47.10sec and is odds-on favorite to give Australia the gold in the sport's blue riband event and lead them to victory in the coveted 4x100m free relay.

The US have a "Missile" of their own, however, in 17-year-old Missy Franklin, who is set to become the first US woman to swim seven events at one Games.

Franklin has downplayed comparisons to Phelps, but US women's head coach Teri McKeever thinks the youngster has what it takes to be a force on the Olympic scene and part of "the next generation of great swimmers".

"The US is the big challenge. They have dominated swimming for 100 years," acknowledges Australian head coach Leigh Nugent. "There are other players who are making it tougher for us to stay in that number two position."

Without a doubt that includes China, who claimed just one gold medal at the Water Cube four years ago, but have since grabbed four golds at the 2009 world championships and five at the 2011 worlds in Shanghai.

Sun Yang was a star in Shanghai, breaking Aussie Grant Hackett's iconic 1500m freestyle world record.

Ye Shiwen won the women's 200m medley world title, part of a strong Chinese showing that had head coach Yao Zhengjie speaking of Olympic "breakthroughs" in London.

China's Wu Peng signalled his intentions in May with a confidence-building 200m fly victory over Phelps at a Grand Prix meeting in the United States.

South Korea's Park Tae-Hwan, defending his 400m freestyle title from Beijing, gives Asia another contender.

Hosts Britain, who saw Rebecca Adlington end a 48-year drought for British women swimmers with her 400m and 800m freestle titles in Beijing, will hope to see her repeat in home waters.

Elsewhere in Europe, Ranomi Kromowidjojo of the Netherlands owns the fastest times in the world this year in the 50m and 100m freestyle.

In the 200m free, 2008 gold medallist Federica Pellegrini faces a strong challenge from France's Camille Muffat, whose time of 1:54.66 is the fastest ever in the textile suits now mandated by FINA.

The ban on polyurethane "supersuits" means that racing, not records, will be at the fore.

"We're back to a little more true sport," US coach Troy said.

Even so, world records aren't out of the question, although no one expects to approach the 25 set in Beijing.

Australian coach Michael Bohl predicted "three or four" world marks might fall.

"You're probably going to see a couple," Phelps predicted, noting that the Olympics still energize swimmers like no other event.

"This is the Olympic Games, the biggest of the big," Phelps said. "It's the Super Bowl of swimming." (AFP)