A British diver and his American partner who drifted for 19 hours in shark-infested waters off Australia are under mounting pressure to compensate their rescuers over the search cost of up to A$400,000 (£194,000).

As they flew to New York today with a celebrity agent, Richard Neely, 38, and Allyson Dalton, 40, faced intense public demands to repay some of the costs after selling their story for up to 500,000 pounds.

Mr Neely, of Swaffham, Norfolk, told Australian television that the couple had dive insurance and added that, “we are also more than happy to donate to them”.

But John Lippmann, of the insurers Divers Alert Network, said that only the evacuation costs from the time the couple were plucked from the coast of Queensland could be claimed.

“The search through the night would not be coverable,” Mr Lippmann said.

Anna Bligh, the Premier of Queensland, had earlier suggested that the couple should contribute towards the costs of the operation, which involved seven helicopters, three planes and six boats.

“If they are going to profit from their story I don't think a contribution back would go astray. It would be a very welcome gesture,” she said.

The debate over costs came as the couple accused OzSail, the company that ferried the party to the Great Barrier Reef at the weekend, of looking for them in the wrong place. They also traded accusations with fellow divers over whether they had ignored instructions and whether they could have surfaced 200m from the charter boat as claimed.

Rebecca Sharkey, 24, a British backpacker and fellow diver, said that Mr Neely and Ms Dalton had been at the back of the boat and were discussing a plan to find exotic marine life during the final briefing.

“If you feel the current, you’ve gone outside the lagoon. Come straight back, and if you can’t come back for whatever reason, surface straight away ,” Ms Sharkey said last night. “That was the strict instructions.”

Matt Cawkwell, another of the 18 tourists in the party, said: “You got the impression he thought he knew better.”

Fraser Yule, the manager OzSail, said that the crew had done everything possible and questioned why four people with high-powered binoculars on had not spotted them.

But Mr Neely rejected the claims and said that the tour leader had privately told him of a passage through to the outside of the lagoon, which they had found but had been unable to find again.

They went missing at Bait Reef on Friday and it was not until Saturday morning that they were rescued when an aircraft spotted them floating 7.8 nautical miles from where they were last seen.

Ms Dalton recalled her horror last night at the moment she had realised that a dinghy they had watched ferry other divers to the Pacific Star charter boat was not returning for them.

“Each moment ticked by and we were drifting further and further away and we realised they were not coming,” she said.

After tieing themselves together and huddling to share body heat, they reached their lowest ebb in the early hours of Saturday, Mr Neely said. It was during these dark hours that Ms Dalton doubted her ability to go on.

“I remember that I said: ‘Yes you can, we have to, this is not our time’,” Mr Neely said.

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