A bus heading from Stockholm to Berlin has come off a major road in north-eastern Germany and overturned, authorities said.

Six people were seriously injured and a further 10 slightly hurt.

Police said the incident happened at about 6.30am local time at Linstow, near Rostock, on the A19 autobahn.

Germany Bus Accident
A bus sits beside the Autobahn A 19 in Linstow near Rostock (Bernd Wuestneck/dpa/AP)

Photos from the scene showed the bus lying on its side.

FlixBus, the main operator of long-distance buses in Germany, said the bus was heading from Stockholm to Berlin via Copenhagen. Ferries from Scandinavia arrive in Rostock.

Police said there were 61 passengers and two drivers on board from 22 countries

It was not immediately clear why the bus left the road. No other vehicles were involved.

Police said the driver was questioned and a breathalyser test showed an alcohol level of zero.

Investigators are analysing an on-board data recorder to try to understand the accident.