Secretary for Environment and Ecology Tse Chin-wan on Tuesday said the government aimed to step up testing of food products from Japan as the country planned to release contaminated water from the destroyed Fukushima nuclear power station later this year.

Speaking at a Legco panel meeting, the minister said the government had tested more than 770,000 samples of food products from Japan since the 2011 Fukushima disaster, and officers will step up testing from April using new equipment.

Tse said the authorities will decide later whether to suspend importation of aquatic food products from specific Japanese prefectures or require them to provide a radiation level report on imported food products.

Lawmaker Yang Wing-kit questioned if restricting food products from a few Japanese prefectures is enough.

"Will you consider extending the regulation to the entirety of Japan? We have ocean currents and the nuclear waste water will be brought to other parts of Japan through ocean currents. Import controls on several prefectures are not enough," Yang said.

"We are considering a very wide scope. We are not just considering import control on certain prefectures," Tse said.

"However, according to our information at hand, Fukushima and the nearby four prefectures will be the ones with the highest risks. When waste water is being discharged, it will become more diluted further away from the source."

He said decisions will depend on the risk assessment conducted by the International Atomic Energy Agency.

DAB lawmaker Steven Ho said the SAR government should have a set of emergency measures in place.

"The Japanese government said the water was drinkable and the treated water could be used for culturing fish. But they didn't consume the fish themselves... It's better to believe our own experts than the Japanese experts," he said.