German car giant Volkswagen aided Brazil's 1964-85 military government in identifying and persecuting political dissenters among its workforce in the country, a historian commissioned by the group said Monday.

"I can say that there was a regular cooperation between the security staff at VW Brazil and the regime's police apparatus," Christopher Kopper of Bielefeld University told the Sueddeutsche Zeitung newspaper and broadcasters NDR and WDR.

VW bosses commissioned Kopper to research the group's activities in the South American country in November 2016.

A spokesman for the car group told AFP Monday that "we should first of all wait for the final report and the results before commenting on them in detail and agreeing on what measures to take".