An accomplice of Heinrich Boere, the former Nazi SS member on trial for murdering Dutch civilians during World War II, has testified that the SS were afraid of what would happen if they didn't follow orders.

Dutchman Jacobus Petrus Besteman testified on Friday by video link from the Netherlands.

"All those who participated were afraid of not following orders. It was very dangerous," he told the state court in the western German border city of Aachen.

Besteman added, however, that he never witnessed officers being punished for not following execution orders.