The Food Standards Agency said the turkey producer was keeping the products back because they may contain meat from a restricted zone in Hungary. The FSA is waiting for the Hungarian authorities to confirm the origin of the meat.
Bernard Matthews was voluntarily holding the products at two cold stores to keep them out of the food chain, it added.
The FSA said there was a "remote possibility" meat in the products came from the restricted zone, which would make them illegal for sale in the UK. However, it continued to insist the turkey products did not pose a food safety risk.
Bernard Matthews said it had voluntarily agreed to temporarily suspend movements of frozen products containing Hungarian meat for 48 hours.