My fear this is going to create a deterrent to ships' masters from going to the assistance of people in distress

Richard Shaw, maritime law expert

It is a maritime tradition that vessels go to the nearest port in an emergency, enshrined in the International Maritime Organisation's (IMO) Safety of Life at Sea convention (Solas).

But in this case it appears that other concerns, particularly Australia's tough stance on illegal immigration, have taken precedence.

Richard Shaw, a senior research fellow at Southampton University and retired solicitor specialising in maritime law told BBC News Online he believes the Tampa case may set an unfortunate precedent.

Deterrent

"My fear this is going to create a deterrent to ships' masters from going to the assistance of people in distress," he said.

"If they're on the phone to the head office in Norway or London or wherever, the lawyer is going to say, 'well, where are you planning to take these people?'

"There's probably no quick answer to that because states around the world are becoming more reluctant to take in migrants in these circumstances."

United Nations conventions concur with maritime traditions. Norway's Foreign Minister Thorbjoern Jagland has said that under a 1951 international convention, rescue traditions particularly apply to refugees.

But Professor Guy Goodwin Gill, a specialist in international refugee law, told the BBC that international law is not very clear on how boat people should be handled.

"There are gaps in the international regime of refugee protection. Although on the one hand the ship's master has a duty to rescue anyone in distress - including a refugee - there is no international rule governing how [they] should be treated thereafter."

Huge task

Australia - responsible for one of the world's largest sea areas - faces a huge task in policing its waters.

The refugees were picked up on Sunday

Under the UN's Convention on the Law of the Sea, (Unclos) it has either sovereignty or sovereign rights over some 11 million square kilometres of ocean, and a further 5.1 million of continental shelf.

Its territorial waters extend for 12 nautical miles (22km) out to sea.

Within this distance authorities may impose comprehensive controls - but government regulations stipulate that officials "must respect the innocent passage of foreign vessels".

In June, the IMO addressed the growing problem of of illegal migrants being transported, knowingly or otherwise, on board cargo ships.

'Unsafe practices'

A committee of the organisation approved amendments aimed at fighting what it described as "unsafe practices associated with the trafficking or transport of illegal migrants by sea".

The amendments also warn that "carrying a large number of migrants on board a cargo ship... operating international voyages", violate the Solas convention.

The IMO ruled that given these concerns "it is not contrary to request a flag state to authorise a warship of another state to visit a vessel".

The committee also invited member governments to sign and ratify the United Nations' Protocol Against the Smuggling of Migrants by Land, Sea and Air at the earliest opportunity.