Once upon a time it was an unremarkable village in the former East Germany, with a rather misleading name: Himmelpfort, or Heaven's Gate, they call it, though there is not that much heavenly about it.

No matter. The name has proven enough in recent years to attract an annual deluge of letters to Father Christmas, such that Himmelpfort has reinvented itself as Santa's principal sorting office. Last year the village received more than 300,000 letters, of which more than 15,000 came from abroad. The old redbrick village schoolhouse has been turned into one of seven official Christmas post offices designed to process the mail. Every letter gets a reply with the official Himmelpfort Christmas stamp.

The yuletide postal service had humble beginnings. Back in 1984, two children wrote to Father Christmas at Himmelpfort and a post office worker, Konni Matzke, not sure what to do at first, decided to write back. "Word got out and by 1987 we received 75 letters. And it was lovely – mothers sent packets of coffee and homemade cookies to say thank you to Father Christmas."

After the fall of the Berlin Wall, things got even busier, with about 1,000 letters arriving each year, and the village post office was soon overwhelmed. In 1995 Deutsche Post, the state postal service, stepped in to help organise the responses. Now Santa Claus, along with his 20 helpers – the "Christmas Angels" – spend from early November until Christmas Eve replying to each and every one.

Last year, letters came from 81 countries, and Father Christmas points to a map on the wall to show some of the far-flung places from which children have written. There are pins in South Africa, Alaska, New Zealand, Chile, Japan and even the south Pacific island of Vanuatu. Replies are sent out in 17 foreign languages.

For some reason, most foreign letters come from Asia, although neighbouring Poles are also enthusiastic about writing to Himmelpfort, and British and Irish children have also written to Father Christmas here.

Santa Claus tells the Guardian that there are sometimes differences in the letters he gets from outside Germany. "Children from the other countries don't always just ask for things, but also tell me a bit about their lives and how they are doing."

He says he has also noticed that in recent years children, particularly older ones, have started to ask for more electronic toys. "There are more requests for MP3 players, games consoles and mobile phones, but I still also get asked for very traditional presents like pirate ships and dolls."

Every year about 15,000 visitors come to Himmelpfort's Christmas post office, either individually or on school trips, so that the children get the chance to hand over their letters to Father Christmas in person.

Ines Krause, one of four kindergarten teachers accompanying a class from Berlin, says the children have been extremely excited about seeing Santa ever since they wrote their letters in early December. "And they are also really curious to see if Father Christmas will reply. They are going to be waiting every day for the post to arrive."

That was one of the ideas behind the decision to finance the Christmas post offices, says a Deutsche Post spokesman, Rolf Schulz.

"We want to encourage children to write letters in an age when the internet, email and texting are so widespread. We want to support this experience and to show how great it is when a letter arrives in your postbox."

Matzke says that it is not just small children who write to the man in red. Last year a woman wrote to say that she and her partner had been trying to have a child and asked if Santa Claus could grant them their wish. This year they sent photographs of their newborn child.

And two years ago a letter arrived from a 94-year-old man from Switzerland. "He wrote to say that he was happy and had had a good life and now all he wanted was a letter from Father Christmas from Himmelpfort."