Simon Richards of The Freedom Organisation said: "Please boycott @GreggsOfficial to protest against its sick anti-Christian Advent Calendar".
Greggs has apologised for its Christmas advert that replaces the baby Jesus with a sausage role in the nativity scene.
Bakery chain Greggs has released an advent calendar - with sausage rolls and pasties behind the doors instead of chocolates.
"They should donate every penny of their profits to @salvationarmyuk".
The contentious image, which we have reproduced above exclusively in the interests of news reporting, shows a sausage roll, partially bitten into, revealing the sacred flesh of the holy snack within the nativity scene.
"What cowards these people are: we all know that they would never dare insult other religions!"
Rev Mark Edwards, vicar at St Matthew's Church and St Cuthbert's Church in Newcastle, told the Evening Chronicle he was appalled by the photo.
The tokens can be taken into any branch of Greggs and exchanged for a different treat everyday, such as a Festive Bake, a Christmas latte, a mince pie or the bakery chain's signature sausage roll.
"Novelty advent calendars have been around for years, so we thought it was time to take the concept up a notch", added the food-to-go retailer.
The nativity scene is just one of the festive images hidden behind doors that has been given a uniquely Greggs twist.
Earlier this week, the bakers announced it would be selling "the ultimate Christmas gift for every Greggs fan".