Consumer advocacy groups have called on the authorities to disclose the names of 12 Japanese restaurants that serve fish imported from Fukushima in Japan for the sake of public safety.
The demand came despite Thai authorities asserting that the imported fish is safe for human consumption.
According to a recent news report by the Japan Times, Thailand is the first country to import fish from the area since the March 2011 nuclear crisis in the area.
A 110kg shipment of fresh flatfish was sent to Thailand from a port in Soma on Friday, to be served at 12 Japanese restaurants in Bangkok.
The shipment is the first such export since the nuclear crisis, according to the report which raised concerns about radioactive contamination.
The Stop Global Warming Association has urged the Food and Drug Administration (FDA) to protect consumers by revealing the names of importers and restaurants and calling on those eateries to put up a sign that they serve "fish from Fukushima".
"This is to help diners decide make an informed decision. If no action is taken, the association will consider taking legal action against the parties involved," it said.
Saree Ongsomwang, secretary-general of the Foundation for Consumers, also called on authorities to reveal the names of the restaurants and re-examine the imports as well as urged the restaurants to delay further shipments from Fukushima.
The FDA and the Fisheries Department jointly held a press conference to insist on the safety of the imported catches.
FDA secretary-general Dr Wanchai Satayawutthipong said the FDA has a set of strict regulations on the import of radiation-tainted food including safety limits and certificates of origin requirements.
The FDA has worked closely with the Japanese health authorities to ensure the safety of imported food, he said.
According to Dr Wanchai, the Japanese Health Ministry last year examined 7,408 fish samples taken from the sea in Fukushima and found only eight samples that had excess amounts of radioactive contamination.
They were cherry salmon and white-spotted char.
However, these species were not among those imported for sale or consumption in Thailand, he said.
The FDA has conducted random tests on fish imported from Japan since 2011 and never found excessive radioactive contamination. The Department of Medical Sciences also conducted similar tests in 2016 and did not find any evidence of contamination with the Caesium-137 isotope, which had been found in some food products imported from Japan.