© ABCRare Arctic bird, the Grey Phalarope, has been spotted in a Darwin sewerage pond years after it was last sighted in Australia
Bird watchers are furious at being blocked from a Darwin sewerage facility where a lost Arctic bird has been spotted, because a crocodile is lurking in the ponds.

The grey phalarope, with its dirty white feathers, has been floating around the Leanyer sewage facility for the last few days.

Local bird watchers do not know how it got to Darwin, as it usually breeds in the Arctic tundra and there have been no sightings of it in Australia for years.

Experts speculate it broke away from pack of the migrating birds and got lost.

Twitchers from around the country are flying into the Territory today to get a rare glimpse of the bird.

But the owner of the site, Power and Water, has ruffled feathers with news it is barricading the sewerage ponds because of heavy rain and the arrival of a crocodile.

Power and Water says it would like to help the birdwatchers but the ponds must remain closed until safety concerns are addressed.

"Over this wet season there has been closures, we've also been undertaking de-sludging works which means there's heavy machinery around," John Pudney from Power and Water said.

"It's a difficult time for us, we'd really like to help out, but the safety of the public is fundamental."