Sainsbury's, Britain's second-biggest supermarket group, has ordered more turkeys for Christmas this year than last year, giving it a buffer in case avian flu hinders supply, reported Reuters.

Britain is facing its largest-ever outbreak of avian influenza and is seeing rapid escalation in the number of cases on commercial farms, raising fears of a shortage of turkeys for the Christmas table.

"Avian flu is a serious issue and one that we're watching very closely and we're not complacent ... our teams are all over this," Sainsbury's Chief Executive Simon Roberts told reporters after the group reported first half results.

He said the group was well prepared.

"We've actually ordered more turkeys overall this year than we sold last year, so we've a buffer overall in our plan," he said.

Also, frozen turkeys, which represent about a third of Sainsbury's turkey volume, had already been culled and frozen, he said.

Market leader Tesco said last month it expected to be able to satisfy demand for turkeys this Christmas.

Roberts noted that there were fears over turkey supply last year due to a shortage of poultry workers and CO2 gas.

"In the end ... we had plenty of turkeys for everyone last year, in fact we probably had a little more than we needed," he said.

He also highlighted a trend for shoppers to increasingly look at alternatives to turkey at Christmas.

"We've seen a real move into gammon and beef in recent years," he said.