A Somerset man has described meeting "Jaws" as a great white shark nudged his dinghy as he fished in Australia, near to where a man was killed just days before.

In the latest encounter, Paul Vickery and his wife Lesley, originally from Somerset, were menaced by a great white shark as big as their 4.2m dinghy off a beach south of Perth on Tuesday.

He said the shark "appeared from nowhere", then circled the aluminum dinghy at about 9.30am before lurching at them.

Mr Vickery, 46, who has emigrated to Australia, said: "It was just like Jaws except he had his mouth closed. The boat lurched when he rolled over and he either touched it or the displacement of water made us tip. It scared the 'bejesus' out of us."

The couple were crabbing in waters about half a kilometre from the Port Kennedy beach where 51-year-old banker Brian Guest was killed by a shark on Saturday.

Mr Vickery said: "It was a huge great one, bigger than the boat probably about five metres.

"It looked so beautiful in the water. I feel very sorry for that family, you know for Brian Guest's family, that got taken the other day. I'm very sorry about that, but I don't know, they are so majestic and so beautiful you know it was quite a thrill to see it."

But he said he and his wife "froze with fright" as the shark lifted its head out of the water centimetres from their boat.

The incident occurred about 500 metres north of the spot where Mr Guest was believed to have been snatched by a shark on Saturday morning. Mr Guest vanished while snorkelling for crabs with his son. Witnesses reported seeing a fin and splashing in the water before the sea turned red.

Mr Guest's shredded wetsuit was recovered but a four-day air and sea search has failed to find his body.

Mr Vickery said they usually snorkelled for crabs, but on Tuesday chose to take out their dinghy because his wife was nervous after the recent shark attack. "The wife didn't want to go out because of what happened to that poor man but I talked her into it," he said.

Mrs Vickery added: "It just appeared like a submarine would come up. We never heard or saw anything," she said. "I was petrified. It was too close for comfort. We only have a little dinghy and it was a lot bigger than it."

The couple quickly pulled up anchor. Mrs Vickery said: "I just turned to my husband and said: 'Get us out of here now'. I was petrified."

A fisheries department boat, which had been searching for Mr Guest's body, escorted them to shore. Swimmers were evacuated from the water and two beaches have been closed indefinitely.

Fisheries officers spotted the shark feeding in the shallows a short time later but lost sight of it when it moved into deeper water.

A fisheries spokesman said it was impossible to tell if it was the same shark that killed Mr Guest. Mr Guest's family requested last weekend that authorities did not kill the shark.