The Olympic flame returned to Australia on Friday for the first leg of a six-week global relay leading up to the Athens Games in August.

Greeted by the sort of security normally reserved for heads of state, a small lantern carrying the flame arrived at Sydney international airport on a chartered jumbo named Zeus.

The lantern was officially received by John Anderson, Australia's acting Prime Minister with John Howard overseas, before being transported to the Sydney Opera House for a brief ceremony with Aboriginal and Greek dancers and the start of the relay.

The first torchbearer was Cathy Freeman, who lit the cauldron to signal the start of the 2000 Sydney Olympics before winning a gold medal in the 400 metres.

Freeman held her torch to the lantern then emerged from a circle of olives with it alight and set off on a short jog around the harbour foreshore before handing over to the next runner.

"I'm really proud, very proud to be here today carrying the flame and hopefully uniting the world," Freeman told reporters.

"I'm very proud of my history, my Olympic history, not just because I won a gold medal in Sydney, just because I'm an Olympian and all of the messages that the Olympic movement are all about are really special to me."

FAMOUS LANDMARKS

Rekindling memories of the Sydney Games, the torch was passed from one bearer to the next on a specially marked route that passed through the city's most famous landmarks including the Harbour Bridge and Bondi Beach.

It was due to reach Sydney's Olympic stadium at Homebush Bay on Friday evening where former Australia cricket captain Steve Waugh would relight the cauldron.

The list of torchbearers was a who's who of Australian sport including Olympic swimming champions Susie O'Neill and Kieren Perkins but also involved members of the local Greek community and sponsors.

"The image of the flame being carried towards its destination has inspired and excited people the world over," Australian Olympic Committee president John Coates said.

"The flame reminds us of those great objectives of the Olympic spirit of peace, of fair play, of friendship."

The flame was to travel to Melbourne, host of the 1956 Olympics, on Saturday before leaving Australia for Tokyo on a whistle-stop tour that will take in 33 cities in 34 days and reach all five continents for the first time.

Around 11,000 torchbearers from around the world are expected to carry the flame on the relay.

The flame, which was lit from the sun's rays in Olympia on March 25, returns to Greece on July 9 for a final homecoming tour before entering the Olympic stadium to light the cauldron on August 13.