Levels of melamine up to 30 times higher than authorised were discovered at the beginning of November in western France after some 1,000 tonnes of contaminated feed was consumed by farm birds, cooperative Terrena said.

TheStar Online reports that melamine-tainted formula was found earlier this year in China, where thousands of children fell ill and several died.

The chemical, normally used to make plastics, has been found in milk power, wheat gluten and other Chinese-made ingredients used in products ranging from pet food to candy.

"Tests carried out show that there is no risk for human health," said Terrena spokesman Christophe Courousse.

Terrena had lodged a complaint with the producer and halted all imports of Chinese soymeal, Terrena said.

The findings did not prompt the withdrawal of any poultry products from supermarkets after French food safety agency Afssa deemed that no risk to human health existed.

Melamine's ability to make foods appear to have higher amounts of protein during testing has made it a cheap but dangerous substitute that can damage the kidneys.