The driver of an excavator was killed and 13 other people injured when a World War II-era bomb blew up during earthworks in Germany, police said.

The blast wave from the sleeper bomb blew out nearby house and car windows, ripped off roof tiles and could be felt several kilometres away, said police and residents.

The accident on Friday, in which two of the wounded suffered serious injuries, shook an industrial area in the town of Euskirchen, near the former capital Bonn in western Germany.

"During earth works an excavator hit a World War II bomb which exploded," a local police spokesman told AFP, adding that the type of munition was still being investigated.

"There was a huge blast wave. In the vicinity of the accident site and surrounding streets, home windows shattered and garage doors were pushed in."

The ground below many Germany cities still contains unexploded ordnance dropped by Allied and Soviet forces in the World War II, but most is safely defused when found.