An Australian doctor and cave diving expert is playing a pivotal role in the dangerous mission to save 12 young Thai soccer players and their coach from deep in a water-filled cave.

Adelaide anaesthetist Richard Harris, who has 30 years of diving experience and has led cave rescue and recovery missions before, risked his own life on Saturday to make the treacherous journey to the chamber where the boys have been trapped for 15 days.

It was on his advice that the first four boys were cleared to make the incredibly dangerous journey out of the flooded cave complex, emerging alive on Sunday night.

Foreign Affairs Minister Julie Bishop says the doctor’s expertise is in high demand as the rescue mission rolls on, with the aid of 19 Australians.

“He has a diving support partner with him as well. The Australian doctor was in the cave – he was part of the medical assessment to determine that the boys were fit enough to dive and swim to freedom,” she said on Monday.

Dr Harris continues to play a key role in the ongoing international effort to get the remaining eight boys and their coach to safety.

Rescue divers and the boys must dive, swim and climb their way to safety along a pitch-black tunnel that at points is barely big enough to allow an adult to wriggle through.

Those who know Dr Harris say he has ‘unique skills’. Photo: Facebook

Dr Harris’ unique combination of skills meant he was perfect for the task, Bill Griggs, his former boss at the South Australian Ambulance Service’s MedSTAR emergency medical retrieval team, told the ABC.

“To do cave-diving, you have to be all about attention to detail and you have to be meticulous,” Dr Griggs told ABC Radio Adelaide.

David Strike has known Dr Harris for more than 10 years, and says his medical expertise and experience as a cave diver and retrieval expert is invaluable.

“Richard is just one member of a team of uniquely qualified and extraordinary people prepared to sacrifice their own comfort, safety and well-being for the benefit of others. It’s an over-used term, but all of those involved are true heroes,” he told Fairfax media.

Dr Harris has spent the past six years working for MedSTAR, an aeromedical retrieval service for the South Australian ambulance service.

His exploration and photography has gained him a following in the international cave diving community.

All of us at @MedSTAR_SA wish our @drharry64, the rest of the rescue team, and the boys and their coach all the best in Thailand #caveboys #thailandRESCUE

— MedSTAR Retrieval SA (@MedSTAR_SA) July 8, 2018

Dr Harris has extensive cave-diving experience spanning several decades, and has completed complex dives all over the world, including in China, Christmas Island and New Zealand.

He is a leading expert in cave rescue expertise in Australia, and in 2011, had the difficult task of recovering the body of his friend, cave diver Agnes Milowka, after she ran out of air in Tank Cave at Millicent, near Mount Gambier.

After that operation, he spoke of seeing his friend’s body submerged in about 20 metres of water, half a kilometre from the mouth of the cave. She had run out of air after becoming separated from her dive buddy and could not find her way out.

“It looks like she has remained very calm right to the very last breath while she has been working to extricate herself,” Dr Harris told The Australian at the time.

Dr Harris took over as MedSTAR’s head of retrieval co-ordination when Dr Griggs left the position in 2016.

Dr Griggs, who was involved in the medical response to the Bali bombings, said it was Dr Harris’s “fairly unique” combination of medical knowledge and cave diving that led to him being asked to join the Thailand mission.

“He has done many things with the cave diving over many years and he is known to a very small group of people who have that very high level of expertise,” Dr Griggs said.

-with AAP