Two new bird flu cases have been confirmed in Norfolk and Suffolk as the UK's worst-ever outbreak of the disease continues to heap pressure on the region's poultry industry.

Defra said all affected birds will be humanely culled after a highly pathogenic strain of avian influenza was found in chickens at farms near Attleborough and Honington, a village south of Thetford, on September 19.

A 3km Protection Zone and 10km Surveillance Zone have been put in place around both infected premises.

Those zones include increased biosecurity and reporting requirements for poultry keepers including isolating or housing birds, restrictions on the movement of poultry, eggs, meat and carcases.

These are the latest developments in an unprecedented outbreak which has already seen 125 cases of the highly-pathogenic H5N1 strain of avian influenza confirmed by the government across England.

Another case was also confirmed last weekend in a backyard flock of poultry in Little Livermere, near Bury St Edmunds, on September 17.

The most recent Norfolk cases were near Holt on September 3, and at a poultry farm at Gayton, near King's Lynn, on August 21 - just five days after the lifting of a national Avian Influenza Prevention Zone (AIPZ), which enforced strict biosecurity rules for poultry and captive birds.

Defra said the risk to poultry had been reduced to "low", but stressed that all bird keepers should "still follow enhanced measures at all times" to prevent future outbreaks - with "scrupulous biosecurity" being the most effective method of disease control.

John Newton, Norfolk county adviser for the National Farmers' Union (NFU), said the new cases are "concerning news for our region’s vital poultry sector and highlight that avian influenza still poses a risk".

"We would urge all bird keepers to remain vigilant and maintain enhanced biosecurity measures to help prevent future outbreaks," he added.

Although bird flu is potentially devastating to commercial poultry and wild bird flocks, Public Health England (PHE) advises that the risk to public health from the virus is very low and the Food Standards Agency advises that avian influenzas pose a very low food safety risk for UK consumers.