It may not be a white Christmas but it is already on ice as more shoppers fill their freezers with party food, turkey and other festive specialities amid fears of another disrupted end to the year.

Sales of frozen turkey have almost doubled, frozen stuffing is up by a fifth and sales of frozen part-baked bread rolls and other savoury bakery items were up by 9% in Great Britain in the four weeks to 3 October, according to analysts at Kantar.

At the frozen foods specialist Iceland, the figures are even more stark – frozen party food sales have tripled and frozen turkeys are up 400% as shoppers plan ahead.

Richard Walker, the boss of the Iceland chain, said its Christmas website had gone live a month earlier than last year because of customer demand.

However, he said business was steady: “We’re not seeing crazed panic-buying.

Aldi and Tesco have also reported a surge in frozen turkey sales, with many families fearing they will miss out if they leave buying their Christmas meal centrepiece until the last minute. Waitrose said there was still demand for fresh turkeys and its pre-orders were up by well over a third on this time last year.

Concerns about the availability of seasonal goods drove about a quarter of shoppers to start their Christmas shopping in September, according to analysts at Mintel, the highest proportion ever tracked by the market research firm.

Eden Plummer, a consumer insight director at Kantar, said the rise in sales of frozen Christmas foods stood out against an overall fall in frozen sales last month and a general drop in the grocery market as shoppers enjoyed more freedom to dine out than last year when restrictions were in place in various parts of Great Britain.

“This year you can understand that some people want to make sure they have everything they need in advance to make sure they have the celebration they weren’t able to have last year.”

Plummer said that sales of Christmas puddings were up 76% and mince pies up 10% in the period, so there was a general shift towards stocking up on festive foods.

Nick Carroll at the market research firm Mintel said shoppers were turning to frozen and packaged foods as about a fifth said they had found difficulties in purchasing some products because of shortages on shelves.

British turkey producers have laid down a fifth fewer birds than last year, according to the British Poultry Council, because of concerns about finding workers to slaughter and process them. Meat processors have also warned about potential shortages of complex ready-made dishes such as pigs in blankets for the same reason.

There are also concerns about supplies of CO2 which is used in the slaughter of poultry, as high energy prices have hit production across Europe.

“There was an assumption that we would see some snap back to pre-pandemic habits in 2021. However, the news of fuel, product and staff shortages will have created some uncertainty for shoppers,” Carroll said.