An asylum seeker in Germany has been handed a life sentence for stabbing to death a fellow Afghan who had converted to Christianity.

The victim, a 38-year-old mother of four who was with two of her children when she was attacked outside a supermarket in the southern town of Prien am Chiemsee last April, was stabbed 16 times.

The court at Traunstein was told the accused, who was not named, was angry because she had turned her back on Islam. She had asked her 30-year-old attacker if he wanted to convert as well, according to the DPA news agency.

The court was told the attacker had been exposed to violence from a young age and his lawyers asked for leniency. He apologised to the victim's family.

He will serve at least 15 years before he can be considered for parole, but the gravity of the crime means he is unlikely to be freed early, DPA said.

Germany hosts the largest Afghan community in Europe at around 156,000 in 2015, 35,805 of them in Hamburg. Many have fled the country because of the continuing violence and insecurity there and struggle to make new lives elsewhere. In spite of its generous policy toward refugees, German deported the largest number of failed Afghan asylum seekers in 2016, at 3,440.