ISRAEL won Hong Kong's heart with diamonds. But it did not stop there. Now it is diagnosing its sicknesses with electronic wizardry, fending off assassins with specialist airport security systems and guarding her borders with night-vision binoculars. Diamonds are still Israel's biggest export to Hong Kong. Last year alone the trade was worth US$586.7 million, up 12.2 per cent from 1993, and a sixth of the country's $3.5 billion world-wide diamond export business. Cut diamonds account for about 20 per cent of all Israeli exports and the territory is a magnet for jewellery buyers from all over East and South Asia. A large part of what is sold here is re-exported round the region. But Israel has far more to offer than diamonds and oranges. For such a small country it has a way of surprising with the products and services it offers. That is something the Hong Kong Government Supplies Department recognised last year by awarding $7.824 million in contracts to Israel. The biggest was a $6 million contract for Elscint's computer tomography equipment for cross-sectional images of the human body for diagnosis. But others included specialist computer operating software, video-inspection equipment, night-vision binoculars and, more mundanely perhaps, $250,600 of laminated plastic sheet. However, it is in the private sector where most of Israel's $90,000 of non-diamond exports made their mark - an increase of 13 per cent over 1993, with state-of-the-art hi-tech equipment and software a major factor in the success. Trade is, of course, two way. Hong Kong's exports to Israel rose to $281.2 million in 1994, up 13 per cent from the previous year. That included a 45 per cent increase in machinery exports to $127.7 million. Ephraim Aviram, Economic Affairs Consul at the Consulate General in Hong Kong, said: 'Until three years ago, imports from China were more or less forbidden. Although imports from Hong Kong were allowed, they were subject to high tariffs and duties.' All that has changed with the establishment of relations with China in 1992 and Israel's new liberal trade policies which have resulted in slashed tariffs for imported goods. But one of the most exciting products of the expanding Hong Kong-Israel relationship has been locally-based Guardforce's acquisition of a 43 per cent holding in the Israeli aviation security business ICTS. Guardforce's parent company, First Pacific Group, calls this 'part of a move to look for opportunities at the new regional airports in Hong Kong, Macau and Shenzhen'. Tel Aviv-based ICTS (International Consultants on Targeted Security) provides aviation security services at about 40 airports around the world and includes more than 50 airlines among its clientele. ICTS (HK), a joint venture with Guardforce, serves the Asia-Pacific operations, which include aviation security in Hong Kong, Singapore, Thailand, Macau, New Zealand and Fiji. Guardforce Technology also operates a joint venture with Israeli electronics manufacturer Moked Emosh International. Moked's Easilink home security device, activated by a remote control button on the subscriber's wrist or pendant, takes the panic out of a crisis. It connects with a central communications unit which can put you in touch with doctors, emergency services or family members without the need to look up the numbers.