Anton Toia, assigned as liaison officer to the Lions' tour party by the Australian Rugby Union, has died from what is thought to have been a fatal heart attack on a beach close to the squad's hotel.
New Zealander Toia, who lived in Queensland, had worked for the ARU since 1987 and had assisted all major rugby union touring parties to Australia during that time.
The 54-year-old father of three was seen struggling in water by two local surfers on a beach 100 metres from the Lions' hotel in Coffs Harbour and they raised the alarm.
Lions tour manager Donal Lenihan said: "Anton was a very popular member of the touring party and had made a valuable contribution to the Lions since linking up with us three weeks ago.
"Our deep condolences go out to his family and friends at this very sad time."
ARU chief executive John O'Neill said: "He was one of the most popular men in rugby and will be deeply missed."
PA