Dutch farmers imposed a commercial ban after 12 British-raised calves imported in March tested positive for the disease, The Times of London reported Wednesday. Belgian farmers unofficially are refusing to accept British calves and cattle, the British newspaper said.

Exporters said they worry a total ban on British cattle in European Union countries could be enacted by next week, the Times reported.

"People are very worried about possible loss of exports because we are just approaching the main three-month season for export of calves for veal production," said Kim Haywood, National Beef Association director. "If this issue builds momentum in Europe, the consequences could be dire."

The National Farmers' Union, working with British officials in Brussels, is urging that any bans be voluntary.

News of the infection came after Rural Affairs Secretary Hilary Benn rejected any culling to control the disease.

The NFU said it thinks the government's position violates a rule requiring that countries adopt an EU eradication plan for bovine TB. Britain hasn't submitted a formal plan to EU officials in Brussels.