Frozen food producer Findus Nordic said Sunday it would sue French firm Comigel and its suppliers after horsemeat was found in its beef lasagnes.

"This is a breach of contract and fraud," the head of Findus Nordic, Jari Latvanen, said in a statement announcing the legal action.

"Such behaviour on the part of a supplier is unacceptable," he added, noting the meat in its lasagnes was supposed to be French, German or Austrian beef.

Findus has asked its suppliers to certify their meat, but Comigel was the only one to report irregularities, he said.

According to Latvanen, the system had actually worked well because it uncovered the fraud.

"No law can prevent someone from intentionally carrying out fraud, using horsemeat and falsifying documents," he said.