Australian troops have taken control of a Norwegian freighter with 438 asylum seekers on board after it defied orders to stay out of Australian territorial waters. The ship has been stranded in the Indian Ocean since Monday, while three governments argue over which country should accept the migrants.

Australia elite military troops in full camouflage gear boarded the Norwegian cargo ship, Tampa, Wednesday, after it left international waters heading for Australia's Christmas Island.

Australian Prime Minister John Howard told Parliament that the ship defied a clear directive from his government, and therefore "the government was left with no alternative but to instruct the chief of the Australian Defense Force to arrange for defense personnel to board and secure the vessel."

Australia had warned the Norwegian government that if the ship - carrying 438 mostly Afghan asylum seekers - entered Australian waters it would be stopped.

The company which owns the Norwegian ship says the captain, Arne Rinnan, decided to approach Christmas Island because the situation on board the Tampa was getting out of hand.

The vessel rescued the migrants late Sunday, from a sinking Indonesian ferry that had been illegally transporting them to Australia.

Some of 438 asylum seekers are on a hunger strike. Others are suffering from diarrhea, scabies and stomach problems. A number threatened to jump overboard if they did not receive immediate medical attention.

Indonesia has refused to accept the ship or the asylum seekers. But the Australian Government is still negotiating with Indonesia to resolve their fate, arguing Jakarta should take the responsibility.

Australian Foreign Minister Alexander Downer also hopes to negotiate a memorandum of understanding (MOU) with Indonesia to stop the illegal trade of asylum seekers through its waters.

"The MOU will commit the two countries to further cooperative activities to prevent irregular people movements as best we can and obviously as best we can to prevent people smuggling," he explained.

Australia has become a popular destination for thousands of illegal immigrants from the Middle East and South Asia hoping to gain asylum.

Meanwhile, the Norwegian government says it is considering every alternative to resolve the crisis.