THE Royal Navy is preparing to defend the South China Sea from pirates as the Chief Secretary seeks to internationalise the issue of raids on ships leaving Hongkong. The Royal Navy Captain in Charge Hongkong, Captain Tom Sunter, yesterday did not rule out firing on pirates, saying the navy could use the minimum force necessary to repel pirates in international waters. Captain Sunter is spearheading fresh research into what the Royal Navy could do to protect merchant shipping from raids in international waters in the South China Sea. Findings will soon be handed to the Hongkong Government and the Ministry of Defence in London, and are expected to be taken into account by Sir David Ford, who is preparing an official government response on interference to merchant shipping. The policy, tipped to be an inoffensive attempt to seek international solutions to an international problem, will be used to calm diplomatic and industry concerns at new threats to Hongkong's status as a free and safe port. Western diplomats, shipping industry and Marine Department officials now fear some violent pirate raids could be the work of corrupt Chinese Public Security Bureau and Customs officers. International shipping warnings obtained by the South China Morning Post, sourced to United States Navy intelligence reports, note recent attempted interceptions by Chinese gunboats out of Hongkong have included Japanese, Russian and Panamanian ships, aswell as traditional Vietnamese targets. Marine Department briefs and the internationally-circulated US Navy reports merge the two problems for the first time. The US reports, circulated by the Liberian shipping registry in New York, say the attacks, which have involved uniformed Chinese officers operating unmarked patrol-type boats, may be ''officially sanctioned and not random acts of piracy''. The reports urge all US flagged and controlled ships to exercise caution in the seas around Hongkong and the Sakishima Islands, off Taiwan. The Marine Department notes the use of official patrol boats in some of more than 20 armed attacks around Hongkong, detailed for the United Nations' International Maritime Organisation (IMO). The department papers will be presented in London next month to a meeting of the IMO's maritime safety committee. The department will put forward a proposal to get IMO member countries to control the use of firearms on coastal craft, in a move aimed at raising international awareness of both piracy and China's armed interceptions. Meanwhile, the Royal Navy research noted that international maritime conventions allowed for naval intervention to suppress pirate attacks in international waters, naval sources said. The Royal Navy would be unable to intervene in Chinese waters, because international conventions stipulated that such attacks could only be classed as piracy in the open seas. Urgent talks between Hongkong and China on the issue will also be recommended to improve intelligence sharing and hammer out some form of joint action. The Government and British Ministry of Defence will be advised, however, that it would be impractical to send out the Royal Navy's three patrol boats based in Hongkong - HMS Starling, Plover and Peacock - on routine patrols. The Royal Navy in Hongkong would prefer to react to ''specific, defined'' acts of piracy, based on a solid intelligence network, the research notes. Captain Sunter said yesterday he had instigated the research two weeks ago, but would wait to be ordered by the Government and London before reacting. ''We are looking at how we can expand our role in the South China Sea and how best to combat the problem,'' he said. ''I've informed the Royal Navy in London and if I'm told to go on patrol immediately I'd be delighted to do it.'' He underlined the importance of reacting to individual incidents or tip-offs saying: ''Sending ships flogging up and down the coast achieves very little.'' When asked if the navy would fire on attackers, Captain Sunter said: ''In international waters, we would use the minimum force necessary to achieve our aims.'' Each situation would be different under recognised rules of engagement, he said.