Profat TM, the Belgian company which produced the pork fat, declined to comment at the moment.

VWA said: "Since the contaminated raw material is in small quantities and it is then further processed, there is no direct threat to public health."

"The Dutch company involved has informed its clients who bought contaminated products from it and we are taking measures to seize the feed," a VWA spokeswoman said.

Dioxins are one of a number of toxic chemicals that originate in pesticides or industrial processes, leach into rivers and lakes and build up in the flesh of fish and animals.

The Belgian food agency FAVV said on its website it had been informed by the Dutch authorities about the incident.

FAVV is investigating the reasons for the contamination and said no dioxin cases had been reported in Belgium so far.

The Netherlands -- one of the world's top meat exporters and Europe's second biggest animal feed producer -- has been hit by several feed debacles in recent years, including one involving dioxin in feed in 2004.