The UN's International Maritime Organisation (IMO) convention is the first-ever such agreement on shipbreaking, which often exposes workers to asbestos, mercury and other hazardous substances.

The deal requires shipowners to provide an inventory of hazardous materials aboard a ship before it is sent for recycling -- work that is mostly carried out in China, Turkey and south Asia, often by unskilled migrants.

But activists say it fails to end the controversial practice of "beaching," when ships are dumped at high tide and then drift to beaches to be taken apart -- a practice 107 environmental and rights groups have urged the IMO to ban.

"The new convention on ship recycling adopted today won't stop a single toxic ship from being broken on the beach of a developing country," said Ingvild Jenssen, director of NGO Platform on Shipbreaking, an umbrella group of non-governmental organisations.

"It legitimises the infamous breaking yards of India, Pakistan and Bangladesh, and actually rewards these exploitive operations while punishing those companies that have invested in safer and cleaner methods."

Much of the shipbreaking done in developing countries takes place on soft sand beaches, where access for heavy lifting equipment and emergency vehicles is difficult or impossible.

Workers, many of them children, face a high rate of accidents, including the loss of life and limb.

But the IMO defended the agreement without a ban on beaching and proclaimed the Hong Kong conference a success after 66 member states lined up to sign the treaty -- including Australia, Brazil, China and South Africa.

IMO spokesman Lee Adamson said the member states had to deal with reality in an important multi-million dollar industry.

"There is nothing that can force a sovereign state to become party to an international convention should it consider it not in its interests to do so," he told AFP.

He said the treaty, which must now be ratified by individual member states, was "a tremendous step forward in terms of health and safety for workers in the industry and for protection of the environment from end-of-life ships -- it will set standards where none previously existed."

The IMO estimates that between 1990 and 2006, more than 10,000 ships that weighed over 500 gross tons were recycled worldwide.

Breakers pay ship owners by the ton and make their money from re-selling the recovered materials. According to the NGO Platform on Shipbreaking, 80 percent of recycling is done by ill-protected workers on beaches in poor nations.

Yards in less well-regulated parts of the world can pay much more to break up the ships, as they pay lower wages and have less rigorous health and safety laws.

"(A ship owner will get) more than 10 times the price by selling to a yard in Bangladesh than to a yard in the European Union," where regulations are much stricter, said Jenssen.

Presently, ship owners can expect to earn around 300 dollars per ton by selling to a south Asian shipbreaker, she said, down from around 700 dollars, as prices for raw materials have tumbled because of the global economic slowdown.

Beaches provide a poor environment to contain the pollutants released when ships are broken apart, said NGO Platform spokeswoman Helen Pervier.

"No developed country at this meeting would allow a ship to be broken up on its beaches," she said.