Richard Neely, 38, and Alison Dalton, 40, were winched to safety nine miles from where they had been diving near the Whitsunday Islands off the eastern coast. They were rescued after an all-night search involving more than a dozen aircraft and flown to a hospital in Queensland, police said.

"I truly thought we were going to die. Sharks were on our mind the entire time, but neither of us mentioned the 'S' word," Mr Neely told the Sunday Mirror newspaper in an exclusive interview. "We just had to stay positive and calm to help each other through the ordeal and not think about being eaten alive."

A local official credited their survival to their diving experience and ability to remain calm.

"They strapped themselves together using their weight belts, they conserved energy, stayed as a pair and awaited rescue," said Queensland state police Supt Shane Chelepy.

He said the pair became lost on Friday when they resurfaced after diving on a reef and found themselves 200 metres from their chartered dive boat and out of sight of its crew.

An air search was mobilised off the tropical east coast after they failed to rejoin the boat at the scheduled time.

Three aircraft, including a specialised search plane with infrared night vision equipment, searched into the night. The search was expanded at first light with seven helicopters and three more planes.

A rescue helicopter pilot who winched the couple from the ocean said they were in good humour when rescued. "Considering they were out there for 19 hours, they were in very good spirits when they got back," David Williams told Australia's Network Seven television. "They were cracking quite a few jokes about their ordeal."

The Sunday Mirror said Neely is from Swaffham, Norfolk, but recently lived on a boat off Phuket, Thailand, where he worked as a diving instructor. Dalton, his girlfriend of nine months, is a qualified dive master from Sacramento, California, it said.