A second king penguin has been spotted on mainland Tasmania, with one wildlife officer calling the sighting especially rare "unless you're on a tourist ship going to Antarctica".

Key points: A king penguin was spotted by kayakers on a beach at Port Davey in Tasmania's far south-west

A king penguin was spotted by kayakers on a beach at Port Davey in Tasmania's far south-west The species is usually seen 1,500km further south in Sub-Antarctic regions such as Macquarie Island

The species is usually seen 1,500km further south in Sub-Antarctic regions such as Macquarie Island It is the second such unusual sighting this year, but a wildlife officer says it is no cause for concern

The penguin was spotted by kayakers at Port Davey in Tasmania's far south-west.

Wildlife officer Julie McInnes said it was a different penguin to the bird spotted at Seven Mile Beach near Hobart last month.

Dr McInnes said it was unusual to have two king penguins sighted in one year.

"This is a really rare thing for people to see, unless you're on a tourist ship going to Antarctica," Dr McInnes told ABC Radio Hobart.

The birds usually call Macquarie Island, about 1,500 kilometres from Tasmania, home.

"Given the remote location of the second bird, there may be a number of birds that come ashore over the years which are not seen or reported," Dr McInnes said.

She said "vagrant" juvenile penguins were known to come ashore away from their colonies from time to time.

"They can disperse quite a way," she said.

The second king penguin was spotted by kayakers at Port Davey in Tasmania's remote south-west. ( Supplied: Roaring 40s Kayaking )

"They aren't as tied to the colony during that age, they can be at sea for three years and come up in different locations."

Authorities were able to distinguish the second penguin from the first by its coat.

"After it moulted its feathers it was looking pretty shiny and sleek," Dr McInnes said.

"This one has older, worn feathers and hasn't moulted recently."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 21 seconds 21 s Suprise antarctic visitor to Tasmania ( Katri Uibu )

A fish feast before fasting

The first penguin underwent its "catastrophic moult" at Rheban on the state's east coast, after stopping by the busy Seven Mile Beach.

Dr McInnes said it was a rare sight for a king penguin to be in such a populated area.

During the moult, the penguin needs to be onshore for about two weeks because its feathers are no longer waterproof.

The first king penguin was sighted on Seven Mile Beach near Hobart, before conducting its moult on the east coast. ( Supplied: James Smith )

"They find random locations and come ashore, and that seems to have been Tassie for these guys," Dr McInnes said.

She said the second penguin appeared to be in good condition, and "quite fat".

"They do feed up quite a lot beforehand and put on additional body weight," she said.

"By the end they are a lot slimmer, then they head out to sea and feed up again."

Dr McInnes said the first penguin appeared to be very healthy after its moult, and would be on its way back to Macquarie Island.

"They are obviously finding some good local food," she said.

Other 'vagrant' penguins spotted this summer include royal penguins and rockhopper penguins.