Christianne Glossop, chief veterinary officer for Wales, confirmed it was H7N2, a less virulent relative of the deadly H5N1 strain.

The discovery could again raise consumer fears about the safety of the UK's poultry supply, and impact processors operations.

The 30 remaining birds on the farm in Wales where H7N2 was found were slaughtered today and the farm employees and any others who came into close contact are undergoing testing, the Department of Environment, Planning and Countryside (EPC) said today.

In February, a discovery of the H5N1 virus on a Suffolk farm, owned by Bernard Matthews, led to 159,000 birds being slaughtered. The strain was linked to a similar strain found in an outbreak in Hungary in January.

The H7N1 is a low pathogenic strain of the bird flu virus and should not cause serious illness in humans, the EPC stated, quoting the Food Standards Agency.

Officials have implemented the UK's contingency plans for bird flu outbreaks. A 1km restriction zone is in place around the infected premises. No birds or bird products can be moved from the area.

The EPC has asked poultry keepers to observe strict biosecurity measures and report any suspicious signs of a notifiable avian disease to their local Animal Health Divisional Office.

Animal health officers could not confirm whether the disease was caused by a migratory wild bird or by agricultural imports.

Further information will be sent through the National Poultry Register, the EPC said.