French round-the-world sailor Yann Elies, who was rescued by an Australian navy frigate after he fell and broke his leg 1,200 kilometres off the Australian coast, was back on dry land on Monday.

Elies, 34, spent two days in his cabin unable to move before the HMAS Arunta reached him in the Indian Ocean on Saturday.

The ships' commanding officer, Steven Bowater, told ABC radio after docking at Fremantle, Western Australia, that the Arunta arrived just in time to rescue Elies from his 18-metre yacht, the Generali, which was competing in the Vendee Globe race.

"I can tell you that the doctor made an assessment that he would have died if we had not arrived on the scene," Commander Bowater said.

"He wasn't able to get to his painkiller. He wasn't able to get to food and fluids, so it's a good thing that we arrived in such good time."

Elies was injured when he fell to the deck while changing sails in heavy seas 1,200 kilometres south-west of Perth on Thursday.

The ships' doctor, David McIlroy, said Elies broke his left leg, may have a pelvic injury, fractured several ribs and seemed to have a very significant knee injury.

Heavily sedated, he was taken to Royal Perth Hospital for treatment.