An outbreak of bird flu at two Bernard Matthews farms poses “a very low risk” to human health, experts said last night.

Tests carried out by Government vets confirmed that the virus had been found in poultry at sites in Ubbeston, Suffolk, and Yaxham, Norfolk.

But the strain detected is not the pathogenic types H5 and H7, the Department for Environment, Food and Rural Affairs (Defra) said.

A spokesman for Bernard Matthews said: "Bernard Matthews Farms can confirm that Defra have undertaken tests for avian influenza on two of its small breeder farms, following notification from the company of an unusual drop in egg production levels.

"The tests have shown a positive result for an avian influenza virus but Defra have confirmed that this is not either of the highly pathogenic types H5 and H7.

"As a precautionary measure - and out of a duty of care for our employees - we have sought guidance from the Health Protection Agency.

"They have advised that this type of avian influenza poses very low risk to human health and do not recommend providing Tamiflu treatment to our staff."

Defra said the disease was detected following tests which began late on Tuesday.

It said restrictions introduced following the discovery would be confined to the affected premises.

"A routine veterinary investigation is ongoing at poultry premises into the possible presence of a notifiable avian disease," said a Defra spokesman. "Laboratory tests are ongoing and there is no conclusion yet."