Sydney - US citizen Gabe Watson was one step closer to facing a murder trial in Australia on Friday after he was served with a notice to appear in court in the Queensland city of Townsville in February.

An inquiry earlier this year recommend murder charges against Watson over the death of his wife on the Great Barrier Reef five years ago.

Tina Watson, who was 11 days into her honeymoon and on only her second dive, drowned off Townsville while in the company of her husband, an experienced diver.

Watson, who did not attend the inquest into the October 2003 death of his wife, is likely to face extradition proceedings if he doesn't volunteer to return to face court next year.

A witness at the inquest said the couple embraced 15 metres below the surface before separating and moving in different directions. The witness said Watson swam to the surface while his wife sank to the ocean floor.

It was suggested that Watson turned off his wife's oxygen supply, restrained her in what appeared an embrace, then turned the valve back on when she was dead or nearly dead.

An autopsy didn't shed any light on the drowning. Her scuba diving equipment was not found to be faulty.

In a videotaped statement to police, Watson, who was a certified rescue diver, described watching his wife sink, her arms stretched towards him. He said he raised the alarm when he reached the surface.

Lawyers for the Alabama bubble-pack salesman have indicated they will oppose his extradition. Watson's US lawyer, Bob Austin, was quoted as saying the case against his client was "as weak as well water."

"When you look at the facts, and for a motive, there is none," Austin told the Alabama newspaper the Birmingham News. "Gabe got no benefit from Tina's demise, and to think he'd be so stupid to go halfway around the world and do this in front of 25 other people is ludicrous."