The fascist old-boys network closed ranks, enabling its members to shield each other from justice, the study found - helping to explain why so few Nazi war criminals ever went to prison.

"The Nazi-era lawyers went on to cover up old injustice rather than to uncover it and thereby created new injustice," said Heiko Maas, Germany's justice minister, who presented the report Monday.

Though the report only deals with ministry bureaucrats, it roughly matches figures for the wider justice apparatus.

Historians have previously found that in the 1950s, more than 70 per cent of West Germany's top judges also had former Nazi connections.

Safferling said that "at a time when a fierce struggle was underway about punishing Nazi crimes, the old comrades were reluctant to come under the scrutiny of young, unencumbered outsiders".