Amnesty International has accused Australia of violating the 1951 UN Refugee Convention. The human rights group based its accusation on Australian troops boarding a Norwegian vessel carrying asylum seekers to stop it reaching the nearest port and the government proposal to introduce retroactive legislation to allow the ship be forced out of its waters.

The group said that Australia has an obligation to the 434 Afghan asylum seekers drifting in a boat in its waters. A statement issued tonight said: "Australian authorities are undoubtedly seized with the responsibility to examine the passengers' claims for protection in a fair and satisfactory procedure, in accordance with their international obligations".

Amnesty International said that a failure to do this may lead to the refugees being forced back to face persecution in their home countries. Norway said that it has reported Australia's refusal to let the vessel enter a port to the United Nations and the Red Cross.

Australian troops stormed the ship this morning after it crossed into Australian territorial waters. The country's Prime Minister said that seizing it signalled his government's determination to crack down on asylum seekers.

The Tampa had been lying off the remote Australian territory of Christmas Island since Monday. Many of the refugees are on hunger strike and have threatened to riot or jump overboard if they are not allowed to land in Australia.

The Australian Prime Minister said that the troops told the vessel's captain to leave Australian territorial waters. John Howard stood by his decision not to accept the 434, mainly Afghan, refugees.

The Norwegian Prime Minister has criticised Australia for refusing entry to the ship. "One cannot force a ship which the captain deems unfit to sail into international waters," Jens Stoltenberg said. "The Australian Prime Minister did not agree with me," he added.

A spokesman for company that owns the cargo ship said that he was disappointed and astonished that Australia would not accept the refugees and process their applications. Per Rundvig said on Morning Ireland that some of the refugees on board had diseases.

Mr Rundvig also said that Australian medical personnel who have boarded the ship are under orders not to give any treatment to the refugees unless the ship returns to international waters.