SYDNEY - An American salesman pleaded guilty Friday to the manslaughter of his bride while scuba diving on their honeymoon on Australia's Great Barrier Reef more than five years ago.

Bubble wrap salesman David Gabriel Watson, known as Gabe, admitted to the charge during a court hearing in the eastern city of Brisbane in connection with the October 2003 death of his new wife Christina, 26.

Watson, 32, was on honeymoon with his new wife when she drowned during their diving trip at a shipwreck off the city of Townsville 11 days after their wedding in the United States.

A dive instructor found novice scuba diver Tina Watson lying on the bottom of the ocean after Gabe, an experienced diver trained in rescuing panicked divers, had surfaced.

An inquest into her death heard earlier that a fellow diver saw Gabe Watson bear-hugging his wife underwater before he re-surfaced while she sank to the ocean floor.

In mid-2008 a coroner found it was likely Watson killed his wife by holding her underwater and turning off her air supply.

He was later charged with murder but told the court Friday he would plead not guilty to murder but guilty to manslaughter. Prosecutor Brendan Campbell accepted the plea.

Campbell told the court the manslaughter plea had been accepted on the basis that Watson had failed in his duty as her dive buddy by failing to give her emergency oxygen when she needed it.

Watson allowed Tina to sink to the ocean floor without making any serious attempt to rescue her and also failed to inflate her buoyancy vest or remove weights from her belt to allow her to surface, Campbell said.

"He virtually extinguished any chance of her survival," he told the court.

Watson told police his new wife had knocked his mask off and then sank too quickly for him to save her. Prosecutors rejected that argument saying it would not have been possible for her to have sunk so rapidly.

Watson, who has since remarried, voluntarily returned to Australia last month to face his murder charge.

Tina's father Tommy Thomas, her sister Alanda and friend Amanda Phillips travelled from their native Alabama to attend the court hearing.

Prosecutors sought a five-year jail term for Watson, with the possibility of parole after 18 months. He was due to be sentenced later Friday.