Sydney  - Two foreign scuba divers spent the night drifting in shark-infested waters after surfacing to find their Great Barrier Reef dive boat was 200 metres away and the current was carrying them further into the Pacific Ocean, news reports said Saturday.

The pair - a 38-year-old British man and 40-year-old woman from the United States - were alone in the ocean for 20 hours off the Whitsunday Islands on Australia's east coast before being picked up at first light on Saturday.

Deputy Commissioner of Queensland Police Ian Stewart said the captain of the dive boat would be asked why the alarm was not raised until three hours after the divers went missing.

"Obviously there were other divers with that vessel at the time, so we'll have to look at what happened in relation to their recovery or whether they were already back onboard the boat," Stewart said. "There are rules and regulations about keeping an eye on people in the water, so we're going to have to investigate that."

Spotted by a rescue helicopter, they were winched aboard. They are now being treated for mild hypothermia at Townsville General Hospital.

The delay in raising the alarm could hurt Queensland's multi- million-dollar dive industry. Two years ago two British divers spent six hours in the water after seeing their dive boat disappear over the horizon. Again, strong currents had carried them away from their craft.

New safety procedures were introduced after the disappearance and presumed death of of a US couple, Tom and Eileen Lonergan, in 1998. It was two days before the dive boat captain reported the Lonergans missing. The Lonergans were probably dead before a search was launched for them. (dpa)