Arm found where two WA fishermen missing

Divers on a charter boat have made the grim discovery of a human arm in the area off Western Australia's northwest coast where two fishermen have been missing since Sunday night.

The arm will be forensically examined to see if it belongs to one of the men, say police, and it may take several days for results including whether it was lost in a shark attack.

The arm was found on the sea floor near Bills Bay, which is near the Coral Bay town.

Andy Hinds, 57, and Nigel Kitchen, 50, failed to return from their fishing trip off Coral Bay on Sunday night.

The discovery of numerous items from the missing 8.2-metre boat floating on the water raised fears the boat had capsized.

A piece of debris found on Tuesday that was initially believed to be from the boat's hull has now been discounted as being from the vessel, police said.

The men were members of a Rockingham fishing club and were on a holiday with friends.