The 45-year-old from Victoria was a physical training instructor in the Australian Army before a car accident in 1986 left him paralysed below the chest.

He took up wheelchair racing and competed in the sport at the Paralympics in Barcelona in 1992, Atlanta in 1996 and Sydney in 2000, winning three Paralympic golds, two silvers and two bronze medals.

He then retired from athletics and took up wheelchair basketball, and after winning a Paralympic silver medal with his team at Beijing 2008, he helped Australia to glory at London 2012 as they defeated Canada 66-51 in the gold medal match at the Basketball Arena.

But following his glittering Paralympic career, Smith admits it may now be time to walk away from the sport at the very top given that he doesn't intend to go the Rio Paralympics in 2016.

"At this stage there will be no more Games as an athlete," Smith said.

"It's probably time to step back and say I've really enjoyed the experience.

"I can look back and say it has been great and I've taken two sports (athletics and wheelchair basketball) to the top level and been able to succeed at them."

Upon choosing Smith as the Flagbearer for the London 2012 Opening Ceremony, Australia's Paralympic Chef de Mission Jason Hellwig explained exactly why Smith had been bestowed the honour.

Greg Smith was given the honour of carrying the Australian flag at the London 2012 Paralympic Opening Ceremony

"Greg embodies the virtues of the Australian Paralympic Movement to the very highest standards," said Hellwig, who is also the Australian Paralympic Committee (APC) chief executive.

"He is team-orientated and humble but fierce in the heat of competitive battle and enormously successful in his chosen disciplines.

"To be the Australian Flagbearer is a major honour in an athlete's career.

"It is an appointment which considers not only an athlete's performance on the field of play, but equally, the attributes and characteristics that represent the standards, culture and meaning of the Australian Paralympic Movement.

"Greg has represented Australia with distinction in two sports.

"As a wheelchair track and road racer he was one of our best ever.

"As a wheelchair rugby player, he serves his team, his sport and the Paralympic Movement with distinction, focus and humility."

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