France's president said Saturday he wanted to see proper labelling of meat in ready-made meals to avert a repeat of the scandal over horsemeat being passed off as beef.

"I want there to eventually be mandatory labels on the meat contained in prepared meals," Francois Hollande said while visiting an agricultural show in Paris.

"Until then, I will support... all initiatives for voluntary labelling" so that "consumers know the origin of the products they are consuming, especially meat."

A vast food scandal erupted in Europe in January after horsemeat was initially found in so-called beef ready-made meals and burgers in Britain and Ireland. It has since spread as far as Hong Kong.

French firm Spanghero has been at the heart of the scandal after it allegedly passed off 750 tonnes of horsemeat as beef, with the product eventually finding its way into 4.5 million "beef" products sold across Europe.

Meanwhile several horse carcasses containing the drug Phenylbutazone have probably ended up in the human food chain, France's agriculture ministry said Saturday.

Phenylbutazone is an anti-inflammatory treatment for horses which is potentially harmful to humans and by law is supposed to be kept out of the food chain.

A spokesman said the ministry was alerted by British authorities that six tainted carcasses had been exported to France in January, but that the meat had already been processed.

The official told AFP that some of the meat had been recalled but that the equivalent of three carcasses had "probably" been eaten. There was only a "minor" health risk, he said.