Questions still remain after weekend cave diving tragedy

Friends and family have been left devastated after an experienced cave diver died while exploring South Australia's Tank Cave system, west of Mount Gambier.

Gary Gibson's body was discovered in one of the tunnels on Sunday morning after he failed to return to an agreed meeting point.

The 65-year-old Victorian's friend and national director of the Cave Divers Association of Australia, Grant Pearce, told Today he will be sorely missed.

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"Gary is being remembered as a chap who had a lovely personality, he was always known to be wearing a Hawaii shirt and he actually used to be a high school teacher and his students would call him 'Mr Hawaii'," Pearce said.

"He will be missed greatly in the cave diving community with his bubbly spirit and his attention to detail."

Pearce confirmed Gibson was among a team of three who planned to explore the Tank Cave system on Sunday and the dive was "meticulously prepared" ahead of time.

But while each of the party was free to explore individually, the alarm was raised when Gibson failed to show up at an agreed meeting point.

"The other two turned up but when Gary didn't, they returned to the route they followed in the first instance and saw Gary's light in the distance and on closer inspection, they could see he was motionless in the water," Pearce said.

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Pearce clarified there was no rock collapse, nor did Gibson's dive equipment become caught in a narrow passageway.

"We really don't know the circumstances around what happened," he said.

"Officers with the SA Police have been great and are continuing their investigation."

Gibson had years of cave diving experience and Pearce said it's hard to believe something like this could happen to someone with his expertise.

"It took everybody by surprise, including myself," he said.

"Gary would have been the last person I'd expect to come to grief."

Watch the full chat with Grant Pearce in the video above