Investigations were continuing and the case would be handled in accordance with Hong Kong laws, the officer said.

The seizure at Kwai Chung container terminal comes just after South Korea's defence ministry announced an investigation into potentially fatal design flaws in the light tanks, which were launched late last year. It had hoped the vehicle would prove a hot defence export item after being developed over a decade by the ministry and South Korean defence firms.

A South Korean soldier died in July after he was trapped in one of the 26-tonne vehicles, when it sank during a river crossing. Some media reports suggest a faulty pump was to blame in what was supposed to be a routine operation.

It is armed with a 40mm cannon, a 7.63mm machine gun and can fire guided missiles at other tanks. It also has an advanced battle management system that allows it to receive a constant flow of information from sensors on soldiers in the field.

Despite the design problems, the technology of the K-21 would be of interest to many military forces, according to locally based attaches.

'It does seem strange that such a new weapon is being moved about without proper licences,' one envoy said. 'This case will be watched very closely.'

Officers from customs' strategic trade investigation division are handling the case. So far, no one has been arrested. South Korean officials said they had yet to be informed of the seizure and could not comment.

The tank and parts in two containers were loaded on a ship in Saudi Arabia earlier this month and the vessel reached Hong Kong on Saturday. The goods were unloaded at Kwai Chung container terminal.

'The tank was discovered as it was stored in a soft-topped container and its shape could be easily seen from the top of the container,' another customs officer said.

It was to be loaded onto another vessel and leave Hong Kong today. 'Investigations indicate its final destination is Pusan, South Korea,' the officer said.

As stipulated in the Import and Export Ordinance, a licence issued by the director general of trade and industry is required for the import/export/re-export/transshipment of every shipment of strategic commodities.

The maximum penalty for failing to obtain a licence is an unlimited fine and seven years' imprisonment.

Enforcement over such items resulted in 53 people or companies in 41 cases being prosecuted last year, with fines totalling HK$2.22 million. The cases mainly involved liquid crystal polymer, carbon fibre, integrated circuits and information security devices.

In 2000, five Soviet-made armoured military carriers were seized at the Kwai Chung terminal. They had been ordered by state-run China Aviation Industry Supply and Marketing and were bound for Tianjin .

In 2006, customs officers confiscated a Soviet-made MiG-29 fighter jet that was being shipped to the United States.