Aussie climber completes Himalayan grand slam

Only around a dozen people have climbed the world's 14 mountains higher than 8,000 metres.

Friend and fellow mountaineer Zac Zaharias says it is an outstanding achievement.

"It's the grand slam of Himalyan climbing," he said.

"A lot of people talk about the seven summits but that's really a C-grade achievement in relation to what Andrew's done.

"He's done them all bar Everest ... without supplementary oxygen."

But Andrew Lock's latest climb nearly ended in tragedy. He was caught in a storm on descent from the summit of Shishapangma and was forced to sleep out in the open high on the mountain.

The 47-year-old now hopes to climb Mt Everest for the third time and without oxygen.