Former Volkswagen Group CEO Martin Winterkorn, who quit last month, will step down from his remaining posts related to the company, the Sueddeutsche Zeitung newspaper and TV stations NDR and WDR reported, without citing sources. The resignations are expected in the coming days, as soon as a few remaining formalities have been dealt with, they said, according to Reuters.

Winterkorn resigned after the autommaker admitted cheating on diesel emissions tests in the United States but he retained a number of key positions within the group. He is chief executive of Porsche SE, the family owned holding company that controls a majority stake in Volkswagen, as well as chairman of Audi, trucks division Scania and the newly-created Truck & Bus holding.

Labour leaders have been putting pressure on Winterkorn to resign from his remaining posts within the group, one person familiar with the matter told Reuters. The former CEO did not attend a supervisory board meeting at Audi last week, where deputy board head Berthold Huber stood in for him as chairman, the person said.

A person close to the German state of Lower Saxony, VW's second-biggest shareholder, told Reuters he could not imagine that Winterkorn could stay in his various positions at Volkswagen. Porsche SE said it was unaware of any decisions on the matter.

Volkswagen declined to comment. It has previously said it was up to the supervisory boards of the businesses in question to take any decision about Winterkorn's future involvement.