Asian diners are still tucking into sushi at restaurants around the region despite fears that elevated radiation levels in Japan could reach the food chain and contaminate raw ingredients.

In Taiwan's Sushi Express chain, notices informed customers that all seafood was imported before Friday's quake crippled two nuclear plants on Japan's east coast sparking fires and explosions that resulted in radioactivity leaking.

"The current supply and safety of Japanese food is normal," reads a poster on the front door of its 196 restaurants.

A spokesman for the chain said business had not been affected.

But in Hong Kong, used to health scares of its own, including the 2003 SARS outbreak, William Mark, president of the Federation of Hong Kong Restaurant Owners, said he was concerned that business would suffer.

"We're very worried," Mark told AFP.

"The concerns about radioactivity have a long-reaching psychological impact. There is nothing we can do. We're hoping for the best, but we don't see any silver lining in the near future."

Elsewhere, restaurants in Singapore, India and Vietnam serving Japanese cuisine said Wednesday their businesses seemed to be unaffected by the deepening nuclear crisis, at least for now.

Singapore's largest sushi chain Sakae Holdings said customers were still flocking to its outlets, which serve sushi and sashimi on moving conveyor belts as well as popular Japanese cuisine such as teppanyaki.

"So far I think we've been seeing business as usual," a spokeswoman for the firm told AFP.

Customers appeared to be satisfied with assurances that the city's food regulator, the Agri-Food and Veterinary Authority, would screen incoming Japanese produce.

The nuclear crisis deepened Wednesday with another fire at the Fukushima plant, fears a reactor containment vessel may have been damaged, and a radiation spike that forced the temporary evacuation of workers.

Chief Japanese government spokesman Yukio Edano reported a sudden and brief rise in radiation levels at the facility.

In India, which also instituted checks on food imports from Japan, business remained brisk at Japanese supermarket Yamato-Ya.

"People are still buying our fresh fish and seafood," Mukesh Rai, store accountant, told AFP.

The store is well-known in New Delhi and imports seafood and packaged meat from Japan.

Japanese restaurants in Vietnam were similarly unaffected.

"We import notably Kobe beef and certain fish from Japan, whose safety is checked well before importation," said Pham Minh Huyen, sales manager at Japanese restaurant Saigon Sakura in central Hanoi.

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