Sydney - Wallabies great George Smith announced his retirement on Tuesday after a stint with Bristol in the England Premiership, calling time on nearly 20 years playing rugby.

The veteran Australian flanker, who made his Super Rugby debut for the Brumbies in 2000 and went on to win 111 Test caps, said it had been an "absolute privilege".

"Finally the day has come where I officially announce my retirement from professional rugby," the 38-year-old said in statement on the Rugby Australia website.

"Rugby has provided and given me so much. The dreams that I had of playing rugby professionally as a young bloke, I'm fortunate to say that I've lived them and experienced so much more during my time."

Smith singled out former Brumbies and Wallabies coach Eddie Jones, now England coach, for special mention, calling him " a constant supporter and mentor".

"I was extremely lucky in my career to have landed myself in Canberra as a young 19-year-old kid, having the luxury of being tutored by the finest peers and coaches in the game at the ACT Brumbies," he said.

"Those early years in Canberra shaped a part of my rugby identity and further encouraged my personal ambitions to better myself as a rugby player."

Smith played almost 150 games for the Brumbies during a career that also took him to the Reds, French sides Toulon, Lyon and Stade Francais, along with Japan's Suntory and English teams Wasps and Bristol.

He twice won the prestigious John Eales Medal for best Australian player.

Smith did not spell out his next move, but reports in Bristol said he would become defence coach at Tokyo-based Suntory in the Japanese Top League.

This is the same team that sacked him last year following his arrest over the alleged assault of a taxi driver.

He was released after 18 days in police custody after prosecutors decided against pressing charges. Smith denied the allegations.