Animal rights campaigners have called on Lidl to "take Rudolph off the menu" as the discounter became the first grocery multiple in the UK to to introduce reindeer meat to its shelves.
The frozen steaks, £5.99 for a 350g pack, were launched this week under its premium own-label brand Deluxe.
Vegetarian campaign group Viva! condemned Lidl for selling the meat, claiming reindeer was herded in cruel ways.
"Lidl is destroying the magic of Christmas by selling dead reindeer," said campaigns manager Justin Kerswell. "What they term 'luxury cuisine' belies the truth behind an industry that exists to exploit wild animals. Reports show that up to 70% of reindeer killed for meat are calves."
Siberian reindeer were often herded by snowmobiles and in some cases by helicopters and motorbikes, said Kerswell. "This and lassoing them cause huge stress. They can become so distraught their muscle can waste away."
According to research published in academic journal Polar Research, the number of reindeer in Siberia has fallen substantially since the post-Soviet era. "Commercialising reindeer in the west may put numbers under further risk," added Kerswell.
Lidl said the meat came from reindeer fed on "local aromatic herbs and grass. "They live in their natural habitat and have plenty of space to move around," a spokeswoman added.
Lidl is also selling pheasant, venison and springbok in a bid to capitalise on their premium appeal. It has signed up celebrity chefs Lesley Waters and Nick Nairn to produce weekly recipe cards in the festive run-up.
Lidl delays store debut after Armistice Day row (11 November 2010)
Which way forward for the stalling discount chains? (23 October 2010)