Boatpeople land at Melville Island

Melville Island, north of Darwin, was excised from Australia's migration zone by the government today, just hours before a boatload of asylum seekers reached its shores.

The small Indonesian fishing vessel, believed to be carrying up to 20 people including crew and Turkish asylum seekers, arrived at the beach and locals towed the boat 50 metres offshore.

It was only the second vessel to reach Australian territory since the government refused in August 2001 to allow onto the mainland the 430 asylum seekers on the Tampa ahead of an election fought on border protection.

Immigration Minister Amanda Vanstone said the government signed off on the regulations this afternoon but they took effect at midnight, about 12 hours before the Indonesian fishing vessel arrived.

That means those on board will not have access to Australia's legal system.

The navy vessel HMAS Geelong was on its way to Melville to secure the fishing boat.

"If there's anyone in need of treatment I'd assume that the naval officers ... will do the right thing and provide assistance," Senator Vanstone said.

Federal police, Customs and immigration officials had arrived on the island.

Milikapiti community management council chairman Gibson Farmer said a local had gone to the beach to get some water when he discovered the boat with four Indonesian crew and 14 others, believed to be Turkish.

"They said, `Is this Australia?' and we said, `Yes, it's the Tiwi Islands, part of Australia'," Mr Farmer said.

"They were asking for water. When we towed the boat out we gave them something to eat and to drink."

Local police were with the asylum seekers and the airport had been shut to prevent media flying in, Mr Farmer said.

"They said Turkey, Turkey, from Turkey," Mr Farmer said.

"We were shocked. I don't think they were lost."

In July this year, more than 50 Vietnamese asylum seekers were intercepted off Port Hedland and taken to Christmas Island for processing.

The latest arrivals were unlikely to be taken to Darwin, where a new immigration detention centre has never been used, and could be taken to Nauru or Papua New Guinea.

The move to excise Melville Island and the adjacent Bathurst Island drew condemnation. The Australian Democrats said they would seek to disallow the regulations.

"We think it's an appalling principle to have people's legal rights determined on the basis of which part of Australia they're in," Democrats leader Andrew Bartlett said.

"Probably more disturbing than that is the fact the government's managed to bring in these regulations before the boat arrived obviously means that they knew it was coming."

Opposition Leader Simon Crean said he had sought a briefing from the government.

"We know on the last occasion with Tampa how the government manipulated and lied about the Tampa," he said.

"This is a government up to its tricks again by the look of it."

Senator Vanstone urged Labor to support the regulations.

"These islands are just a stone's throw from Indonesia and a convenient dropping off centre for people smugglers to land their cargo," she said.

A government proposal to excise more than 3,000 islands from Australia's migration zone has twice been rejected by the Senate and is a double dissolution election trigger.

- AAP