Aussie diver leaves Laos cave rescue

South Australian diver Josh Richards has left the rescue operation in Laos. (Supplied: Josh Richards)

Australian diver Josh Richards has left Laos, after several days spent trying to rescue miners missing in a cave.

Mr Richards says the requirements of the mission have changed, and someone with his skill set is no longer needed.

Efforts to find and retrieve two men believed to still be in the cave are ongoing, with some members of the international dive team staying back.

The Australian diver taking part in a cave rescue in Laos has left the country, after several days crawling through muddy passages trying to find two people still missing.

Adelaide's Josh Richards arrived in Laos last Friday, after being called into the rescue team on short notice.

Five of the seven people in the cave have been freed, either by the rescue team or by leaving the cave on their own.

With efforts to locate the final two men now splitting between the cave's main entrance and a vertical shaft above the cave, Mr Richards said he left the team to allow people with different skill sets to replace him.

Mr Richards was called in to help navigate tight passages and restrictions underwater. (Supplied: Josh Richards)

"Not only is there not any diving happening because it's too dangerous to push ahead, but even when they do succeed at what they're trying to achieve, there'll be no diving either," Mr Richards told the ABC from Bangkok, as he travelled back to Australia.

Mr Richards said Thai and Laos cave rescue teams were still trying to push into the main mine entrance, pumping out floodwater to possibly regain access.

"We had significant flooding over the past few days," he said.

"Last time I checked in with the team, the crawl from the entrance through to chamber 1 is now completely flooded.

"They've actually gone backwards in a lot of ways trying to remove the water.

"They won't push ahead until all of the water is cleared from the entrance through to chamber 5."

The rescue operations in Laos are focused on the cave's main entrance, and a vertical shaft above. (ABC News)

A vertical shaft, found in the jungle above the cave, has also been investigated to see if it drops into a chamber where the remaining two people could be located.

"I dropped a rock down it, it took about four seconds to hit the ground below so we knew that it was roughly 80 metres deep," Mr Richards said.

"[Fellow diver] Robin [Cuestra] then rappelled into that hole the following day, and found that there are two tunnels heading downwards, but they're both completely choked with rockfall."

Mr R