Lax rules that let in lashings of sushi may be about to close

That a city restaurateur could buy a 342kg bluefin tuna - the most expensive ever sold at Tokyo's Tsukiji market - last Wednesday and have it on the plates of Hong Kong diners by Friday is not just down to the city's appetite for speed and sashimi.

Hong Kong has stretched its lead as the world's biggest importer of Japanese food mainly because it is less demanding about health certification.

But that could change if a new food safety law under consideration is passed.

This cycle of easy supply and high demand has made Hong Kong the number one overseas food market for Japan since 2008, and imports are increasing year on year. In the first half of 2010, the city accounted for 27 per cent of all Japanese food exports, according to figures from the Japan External Trade Organisation (Jetro).

Seafood makes up nearly half of all Japan's food exports and Hong Kong imported 58 per cent more of it between January and November 2010 than it did in the same time period in 2009.

Three tonnes of preserved seafood - such as dried scallops - valued at more than HK$2.6 billion came into the city in the first 11 months of last year, making it Hong Kong's biggest category of food imports.

The US and the mainland require certificates on all seafood imports verifying that the country of origin has deemed it fit for human consumption, according to Caroline Wong, from the office of the director of business development at Jetro.