Thousands of camels face slaughter by helicopter marksmen after they overran an Australian town in search of water.

Around 6,000 animals will be culled in Docker River, population 350, the Northern Territory government said. Camels have been arriving daily for weeks because of drought in the region.

"The community of Docker River is under siege by 6,000 marauding, wild camels," local government minister Rob Knight said.

"This is a very critical situation out there, it's very unusual and it needs urgent action."

The camels, which are not native to Australia but were introduced in the 1840s, have smashed water tanks, approached houses to try to take water from air conditioning units, and knocked down fencing at the small airport runway.

The carcasses of camels killed in stampedes at water storage areas are contaminating the water supply. The government plans to use helicopters to herd the camels outside town next week, where they will be shot and their carcasses left to decay in the desert.

"We don't have the luxury of time because the herd is getting bigger," Mr Knight said.

It is common to see some camels in the remote community, but a continuing drought and an early heat wave have dried up other water sources and forced great numbers of them into town. Much of Australia is gripped by some of the worst drought conditions on record.

In August, the federal government set aside 19 million Australian dollars for a programme to slash the wild camel population, including a possible mass slaughter.

Glenys Oogjes, executive director of national advocacy group Animals Australia, said the plan to kill camels by helicopter was barbaric, and that the community could instead focus on setting up barriers to keep out the camels.

"It's a terrible thing that people react to these events by shooting," she said. "The real concern is the terrible distress and wounding when shot by helicopter. ... There will be terrible suffering."

Camels were first brought to Australia to help explorers travel through the desert, and now an estimated million roam wild across the country.

They compete with sheep and cattle for food, trample vegetation and invade remote settlements in search of water, scaring residents as they tear apart bathrooms and rip up water pipes.