A young New Zealand fur seal has been sunning itself on the steps of the Sydney Opera House and taking regular dips throughout the day in Sydney Harbour as onlookers watch and photograph the visitor.

The juvenile seal has been basking on the VIP steps at the Opera House for most of the day, and wildlife officers barricaded off the area, although spectators were able to enjoy an uninterrupted view of the animal.

Wildlife officers said the seal's arrival in Sydney Harbour was an indication that there had been a recovery in the fur seal population.

"While generally uncommon, we are seeing fur seals take up residence in places like Sydney Harbour and Botany Bay and all up and down the New South Wales coast a little bit more often than they have in previous years," said Geoff Ross, senior wildlife officer at the NSW National Parks and Wildlife Service.

Mr Ross said he believed the three or four-year-old seal may return to Sydney Harbour in the future.

A juvenile New Zealand fur seal takes a nap on the steps of the Sydney Opera House. ( ABC: John Donegan )

"This seal has found other seals that it can associate with, and of course it will remember how comfortable it was here and it will probably come back every year," Mr Ross said.

Harbour Parks ranger Chad Weston said the healthy juvenile seemed perfectly happy to recline on the harbourside steps.

"Once it dries out, it jumps back into the water for a dip, then returns to the steps to sun itself," Mr Weston said.

He said the fur seal was known to extend its range during breeding season, but this seal was one of only half a dozen which have made it as far north as Sydney Harbour this year.

"There is some indication the seal has been in the area for a week or so, but this is the first time it has hauled out at the Opera House location, and it been here since about three or four o'clock this morning," Mr Weston said.

Fur seals making a recovery after nearing extinction

The main fur seal colonies are along the New South Wales south coast at Five Islands off Wollongong and Montague Island off Narooma, Mr Weston said.

Hunting in the 1800s took both New Zealand and Australian fur seals to the brink of extinction but there has been an encouraging rise in numbers over the past decade.

"New Zealand fur seals are recovering more rapidly then their Australian cousins but both species are recovering albeit very slowly after the heavy hunting they suffered during the 1800s," Mr Ross said.

"But we are seeing them on most of our offshore islands in places like Montague Island and the Five Islands off Port Kembla, and fortuitously for all those school holiday goers we are seeing them in Sydney Harbour at the moment."