The death toll in the attack on a Christmas market in the German city of Magdeburg last month has risen to six after a woman succumbed to her injuries, prosecutors said.

Officials in Naumburg said the 52-year-old woman died in hospital, German news agency dpa reported.

The others who died were four women aged 45, 52, 67 and 75, and a nine-year-old boy.

More than 200 people were injured in the December 20 attack.

A 52-year-old woman died days after the attack (dpa via AP)

The suspect, who was arrested immediately after he drove a rented car through the crowded market early on a Friday evening, was identified as a Saudi doctor who arrived in Germany in 2006 and had received permanent residency.

They have said he does not fit the usual profile of perpetrators of extremist attacks.

The man described himself as an ex-Muslim who was highly critical of Islam, and on social media expressed support for the far-right.