Hong Kong will tighten up inspection of food imported by sea after reports that radioactive produce from Japan may have passed through Kwai Chung Container Terminal, the city's Food and Environmental Hygiene Department said on Tuesday.

The department's Director Vivian Lau said there was no inspection check-point at the terminal, however, the officers have been visiting the importers' storehouses to ensure the food was safe to be sold.

Lau said the department has so far found only three highly radioactive vegetable samples among over 240,000 samples tested.

The department stepped up inspections of imports from Japan in March 2011.