A search now has been scaled back to the north Queensland coast, in the hope that the crew made it to shore.

The Kaz II was found with its engine running and a table laid for dinner. But there were no signs of any people.

The 12m (40ft) catamaran was spotted by a helicopter on Wednesday drifting off the Great Barrier Reef, but a rescue team only reached the boat on Friday, and confirmed that there was no one aboard.

"The engine was running, the computers were runningf and there was food and utensils set on the table ready to eat, " said Jon Hall, a spokesman for Queensland's Emergency Management office. "It was a bit strange."

Hall said rescue workers had recovered the boat's Global Positioning System (GPS) device, which might give them more clues as to the crew's whereabouts.

Australian media reported the names of the sailors as skipper Derek Batten, 56, and brothers Peter and James Tunstead, aged 69 and 63.

The three are neighbours in Perth, Western Australia.