The cull of 55,000 Norfolk turkeys is set to be completed "within the next few days" as animal health officials battle to contain the county's bird flu outbreaks.

A highly-pathogenic strain of avian influenza was confirmed this weekend at North Farm in Snetterton, near Attleborough, and at a poultry farm north of East Winch, near King's Lynn.

The farms were rearing 30,000 and 25,000 turkeys respectively, which will all be slaughtered in a bid to prevent further outbreaks from increasing the damage to East Anglia's poultry sector in the run-up to Christmas.

A veterinary investigation is also under way to find out the source of infection and establish how long the disease may have been present on the infected premises.

A Defra spokesman said: "Humane culling of all birds on the infected premises is expected to start as soon as possible and be completed within the next few days.

"We are dealing with these as separate cases. Epidemiological investigations are ongoing at both sites to establish possible source and spread of the infection."

Once the cull has been completed, there is expected to be a two-stage round of disinfection before the poultry sheds can be re-used, with the first overseen by the Animal and Plant Health Agency.

A 3km Protection Zone and a 10km Surveillance Zone have also been put in place around both infected premises to limit the risk of the disease spreading.

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.

Chief veterinary officer, Christine Middlemiss, said: “Bird keepers should remain alert for any signs of disease, report suspected disease immediately and ensure they are maintaining good biosecurity on their premises.

“We are urgently looking for any evidence of disease spread associated with these premises to control and eliminate it.”

Government officials have reassured consumers that Norfolk's turkey culls are not expected to impact supplies of Christmas turkeys, and that bird flu poses a "very low risk" to public health or food safety.