Amid reports about slavery and unlawful fishing in the industry, the European Union has threatened to ban imports of seafood from Thailand because, officials say, the southeast Asian nation has been too lax fighting illegal, unreported and unregulated fishing.

Thailand's share of the EU's annual imports of nearly €21 billion of fish products amounts to about €600 million, and it would join Cambodia, Guinea and Sri Lanka as countries prohibited by the European Commission from exporting seafood to the bloc.

Thailand is the world's third-biggest fish products exporter after China and Norway, but it has been censured by human rights groups and the US for using forced labour on fishing boats. About 15 per cent of its fish exports go to the EU.

The country has six months to get its industry in order or they risk a trade ban, the commission said. European commissioner for environment Karmenu Vella said the yellow card would turn red if Thailand did not implement a "tailor- made" plan to stop the illegal acts.