Restrictions have been put in place at a Suffolk poultry farm after an outbreak of bird flu.
Tests are being carried out after signs of the disease were spotted at a Bernard Matthews farm.
Environment agency Defra confirmed it had been detected but said initial tests were negative for the H5 and H7 strains which are potentially lethal for humans.
However, movement restrictions were in place at the farm on Wednesday and officials have refused to reveal its exact location.
A Defra spokesman said: “We are awaiting further laboratory test results from an on-going investigation into suspect avian disease at a premises in the South East.
“The premises remains under restriction pending further results.
“Public Health England are aware and are ready to take the necessary action pending further test results.”
The lockdown comes after fears of a new epidemic spreading from China where five deaths have been confirmed from the new H7N9 strain of the virus.
Bernard Matthews died in November 2010 but his company still runs 56 farms across Norfolk, Suffolk and Lincolnshire.
A company spokesman said: “Bernard Matthews can confirm that Defra have undertaken tests for avian influenza on one of its farms following notification by the company after some birds showed signs of ill health over the weekend.
The tests have detected the presence of an avian influenza virus, but Defra have confirmed it is not the highly pathogenic types H5 or H7.
“As a precaution, the farm remains currently under movement restrictions but these are expected to be lifted in the next few days.
“Bernard Matthews’ other operations continue to run as normal.”