A Brampton vet is urging people who keep chickens and ducks in their back gardens to be vigilant as a highly contagious strain of bird flu continues to spread.

David McCrea, a vet with Capontree Veterinary Practice, says it is vital poultry be kept indoors in the bid to battle avian flu.

His warning comes as government vets confirmed the disease had been found in a small backyard poultry flock, which included 17 chickens and ducks, several of which have now died, near Settle in North Yorkshire.

The remaining birds have now been humanely culled.

Government officials have said the flock was not housed, despite being just 18km away from a park where the virus had been discovered in a wild wigeon a few days earlier.

The same H5N8 strain of avian flu has been confirmed at a poultry farm in Lincolnshire and at a premises in Carmarthenshire, Wales. It has also been found in wild birds in England, Scotland and Wales.

Just over two weeks ago a bird flu victim was found close to Cumbria after a dead wild peregrine falcoln was discovered in neighbouring Dumfries and Galloway.

"This finding in a backyard flock shows how essential it is for all poultry owners, even those who just keep a few birds as pets, to do everything they can to keep them separate from wild birds, and minimise the risk of them catching avian flu via the environment," said Mr McCrea.

"I have had a few telephone calls from worried poultry keepers seeking advice. I know it is difficult for some to keep their birds inside, but ultimately if people do not take the necessary precautions they are taking the risk of their poultry getting the disease," he added.

Defra chief veterinary officer Nigel Gibbens says birds should be kept in a suitable building where possible, and owners should take precautions such as putting up netting, keeping food and water inside and disinfecting footwear and equipment after contact with birds

A bird flu prevention zone that was in place since last December 6 has been extended until February 28, causing difficulties for free range farmers who could incur increased costs.

Farmers are able to retain their free-range status for a 12-week period of confinement. It is not clear what would happen if there is another extension to the restrictions, which end just days before produce would be prevented from being sold as free range.

There is also a Britain-wide ban on poultry shows and gatherings.