A 26-year-old German man is in custody after a deadly shooting rampage in southwest Germany where six people were killed and another two were injured.

Two teenagers aged 12 and 14 were threatened but not physically harmed.

Local police chief Reiner Moeller said the man allegedly shot his parents and four other family members dead about 12.45pm on Friday local time with a semi-automatic weapon before calling the police and waiting for them to arrest him.

Chief Moeller told reporters the man was waiting for his lawyer to arrive before he was questioned.

“In the house and behind it, six dead people were found, three men aged 36, 65 and 69, and three women aged 36, 56 and 62,” Chief Moeller said, adding that two of the dead were the man’s parents.

One of the two others shot was in a critical condition.

“We don’t yet know the motive, but we assume that it was a family drama, since as we understand they were all related,” he said.

Police found the man waiting unarmed outside the house, a pub where some of the family members also lived.

The fatal shooting was near a building in the town of Rot am See in the federal state of Baden-Wuerttemberg, 135km southeast of Frankfurt.

-with AAP