Respected New Zealand surfer and craftsman Allan Byrne is on life support in an Indonesian hospital following a motorbike accident.

Mr Byrne, who lives on Australia's Gold Coast, was holidaying in Bali ahead of a surfing competition when the accident happened on Friday.

The 62-year-old was taken to hospital with a broken arm, but doctors soon diagnosed a fractured skull and bleeding on the brain, the surfing website Surfersvillage.com reports.

He is now in a coma on life support surrounded by his wife and three adult sons.

Mr Byrne, known to friends as AB and Al, was born in Hamilton and competed at surfing world championships throughout the 1960s and 1970s.

He moved to Australia in the 1970s and founded board shaping company Byrning Spears, where he carved out a reputation for quality channel-bottom boards designed using his knowledge of aerodynamics learned while in the New Zealand Air Force.

According the firm's website, he continues to travel to favourite surfing spots like Whangamata on New Zealand's Coromandel Peninsula, Bali in Indonesia, Kaifu in Japan and the North Shore of Hawaii to work on updating his board designs.

He was due to compete in Bali's Rip Curl Cup at the Padang break, starting this week.