A talented back who could play scrumhalf or flyhalf, Smith won six caps for the Wallabies in 1987, including at the first World Cup, before moving to Europe to study at Oxford and play nine tests for Ireland.
By 1991, his former Wallabies coach Alan Jones had switched codes and he convinced Smith to join him at the Balmain Tigers rugby league team and he played out his career in the 13-man game in Sydney.
After retirement, Smith moved into rugby union coaching and he worked as an assistant under England head coach Martin Johnson from 2008 to 2011.
The Queenslander then had a spell as director of rugby at London Irish before returning home to Australia, where he was most recently head of sport at Sydney private school Scots College.
The school confirmed his death on Wednesday.
Prop Angus Bell, who was coached by Smith as a teenager, paid his respects before the start of a Wallabies news conference on Wednesday.
"Fair to say that I wouldn't have been anywhere near as good without him," the 54-test international told reporters.
"He was a great bloke, a great father, and a great coach. So yeah, very sad."