A king penguin has been spotted more than a thousand kilometres from its home on a southern Tasmanian beach, but a wildlife expert says it may not be lost.

Key points: Conservationists do not know if the bird is lost

Conservationists do not know if the bird is lost They say it could be undergoing a 'catastrophic moult' whereby they lose all their feathers

They say it could be undergoing a 'catastrophic moult' whereby they lose all their feathers King penguins are the second largest penguin species

It is believed to be only the third king penguin sighting on Tasmanian shores in 15 years.

The closest king penguin colony is on Macquarie Island, about 1,500 kilometres south of Hobart.

Marine Conservation Program wildlife officer Dr Julie McInnes said the sighting at Seven Mile Beach was exciting.

"It's a pretty rare thing to see king penguins up here in Tasmania, it's quite a way north from the usual range," Dr McInnes said.

"It's not unheard of, we have seen them a couple of times in different parts of the state."

Dr McInnes said it was not clear if the bird was lost — it may have come ashore to rest after a big fishing trip, or was undergoing its annual moult.

Penguin 'fat and healthy'

Dr McInnes said penguins underwent what is known as a 'catastrophic moult', where they come ashore to lose all their feathers over a few weeks.

"They tend not to go back into the water during that time because their feathers are no longer waterproof," she said.

If it was resting after a big fishing trip, it may be gone from the area within a few days, she said.

Dr McInnes said the penguin was in good condition and did not appear to be injured.

"It looks like quite a fat penguin which is always nice," Dr McInnes said.

She said outside the breeding season penguins would swim well away from colonies in search of food, and did not need to moult at their home base.

King penguins are the second largest penguin species.

The penguin is in a healthy condition, experts say. ( Supplied: James Smith )

Give the penguin space

If moulting, the penguin may be in the area for several weeks, Dr McInnes said.

"Just try and give it some room, don't go close to it. We want to give it ample space so it's safe from people, dogs and boats," she said.

"If it is moulting it can't go back into the water, so the last thing we want to do is scare that animal back into the water."

She said while it had not lost any feathers yet, it could begin to happen over the next couple of days.

"It's a pretty exciting sight, we don't get these birds around too often," Dr McInnes said.

Recreational boater James Smith spotted the penguin on Monday afternoon while out fishing near Lewisham.

King penguins call Macquarie Island home. ( Supplied: Chris Howard )

"I've been boating around here for 35 years and I've never seen anything like it before," Mr Smith said.

"It's pretty amazing, it's a once in a lifetime opportunity. He's a long way from home, that's for sure."

Mr Smith reported the penguin sighting to the Marine Conservation Program.

"I got nice and close without disturbing him, a few people got a bit too close and scared him a bit," he said.

"It's a nice and quiet spot, away from people."

Mr Smith watched the penguin about 20 metres offshore in his boat.

"He's pretty healthy looking, he's pretty fat. I said to the other people nearby 'you'll never see this again'," he said.

