The central government launched a trade complaint at the World Trade Organization on Thursday to challenge South Korea's import bans and additional testing requirements for Japanese food after the 2011 Fukushima nuclear disaster.
South Korea expressed regret at Japan's action and said its ban on some Japanese seafood was necessary and reflected safety concerns.
Japan says several measures taken by South Korea violate the WTO's sanitary and phyto-sanitary (SPS) agreement and Seoul has failed to justify its trade restrictions as required, the WTO said in a statement.