It has a bronze octagonal hilt and comes from a grave in which three people — a man, a woman and a boy — were buried in quick succession with bronze objects, the Bavarian office said in a statement this week.

It is not yet clear whether the three people were related to each other and, if so, how.

German officials say the 3,000-year-old sword is a “very rare” discovery.(Supplied: Bavarian State Office for the Preservation of Monuments)

“The sword and the burial still need to be examined so that our archaeologists can categorise this find more precisely,” the head of the office, Mathias Pfeil, said.

“But we can already say that the state of preservation is extraordinary. A find like this is very rare.”

It is unusual to find swords from the period, but they have emerged from burial mounds that were opened in the 19th century or as individual finds, the office said.

The sword was found among bones in a grave in Germany.(Supplied: Bavarian State Office for the Preservation of Monuments)