"Some dual functions should be reconsidered," one of the sources said.

The number of board seats could be reduced to eight or nine as part of the reshuffle, the sources said, adding that no decisions had been made yet.

The board had swelled to 12 members under predecessor Herbert Diess, whom Blume is due to succeed on Sept. 1.

Both Volkswagen and Porsche declined to comment on the matter.

(Reporting by Jan Schwartz; Writing by Maria Sheahan; Editing by Rachel More)

By Jan Schwartz