More questions have been raised after dive instructor Richard Neely (38) and his 40-year-old American girlfriend Alison Dalton hit national headlines at the weekend when they became separated from their dive boat and ended up alone in shark-infested waters.

In the light of their story – which could now be turned into a film like "Open Water" which featured a similar true case of divers adrift at sea – comments have come out of Australia questioning why the couple, who said they surfaced 200 metres from the boat, had not been seen by crew or other divers.

Trip operator Ozsail said in a statement the couple had not remained on the dive site.

They also claimed they had not followed the instructions of the dive instructor.

However, Mr Neely's father, Stuart (60), who still lives in Swaffham, told the Lynn News yesterday his son was upset by some articles and comments which had appeared in the press. "He is fully experienced. They both knew what they were doing," he said.

Mr Neely, who used to dive with the West Norfolk Sub Aqua Club based at St James' pool in Lynn, is quoted as saying the couple were waving, shouting and whistling and, in addition, had a large surface marker buoy with them.

They admitted they could see other divers climbing back on to the boat, Pacific Star, and lifting their equipment out of the water but thought they could not be seen because of waves and the fact that they were "dangerously drifting further away in the growing swell".

Mr Neely also said helicopters stopped flying at around 3am because "the weather was so bad" and thought those aboard the dive boat had not seen them because they had been looking in the wrong direction.

Meanwhile on Tuesday national newspaper reports quoted one of those on the dive boat as saying the sea had not been choppy. Visibility was so good those on board could see buoys half a mile away.

An investigation has been launched into the incident, which involved seven helicopters, three 'planes and six boats.

The couple were yesterday on their way back to Australia, where they had been holidaying with Mr Neely's sister, Rachel (35), after flying to America for press interviews.

Calls have been made for the couple to pay towards the cost of their rescue after they sold their story for a reported six-figure sum. Mr Neely's father has strongly denied his son received such a large amount.