The boat belonging to a fisherman missing off the West Australian Pilbara coast for more than three days has been found.

Norman Bales has not been seen since setting off from Karratha on Friday night to go mud crabbing in a five-metre dinghy.

However the alert was not sounded until 7.30pm on Sunday when his friend and workmate Stewart Bullen went to his home and realised he had not returned.

His vehicle and boat trailer were found in a car park near Back Beach, about five kilometres from Karratha.

Police said just before 12pm Mr Bales’ dinghy was found floating on the west side of Dixon Island, about 40 kilometres east of Karratha, by another fisherman.

It was almost totally submerged with just the bow showing out of the water, and no sign of Mr Bales.

The comprehensive search involving an aircraft, water police, marine rescue volunteers and army zodiac boats will continue on Tuesday.

Karratha police Senior Sergeant Andy Stevens said earlier on Tuesday the search had been widened.

“We are reviewing the actions of yesterday to ensure our search was done properly and to decide what areas need to be searched today,” he said.

“We are getting more boats on the water. We’ve got four [larger] boats going out from 9am and we hope to have three on the water [early] this morning.”

Norman Bale set off to go crabbing on Friday night. Photo: WA Police

A land search using quad bikes began early on Tuesday, and an aircraft with four spotters aboard was due to begin searching during the day.

But Sergeant Stevens conceded that time was running out to find Mr Bales alive.

“The longer the search goes, the chances that we’ll find this man alive are getting poorer and poorer,” he said.

“The time frame for survival in the water is not very good.”

Police said on Monday it was possible Mr Bale may not have had all the necessary equipment, such as an EPIRB or a radio.

It is believed Mr Bale was planning to head to nearby Airport Creek.

-ABC