Germany's metalworking union and main automotive industry union, IG Metall, is planning a demonstration against Porsche at Volkswagen's annual general meeting in Hamburg on 24 April.

According to the Wolfsburger Allgemeinen Zeitung, the union is protesting against Porsche shareholders and chief executive Wendelin Wiedeking for not have the foresight or the trust to involve Volkswagen workers more in the structure of the new Porsche Holding company.

A meeting of union leaders from all Volkswagen and Audi sites will take place on Monday to discuss details of the action.

"If Porsche does not react soon we will go to Hamburg," said IG Metall chief Frank Patta.

Volkswagen's works council leader, Bernd Osterloh, has talked in the past of a 'hostile takeover' by Porsche, because it has not entered into discussions with workers over the future of the company, and has tried to reduce their influence in decision-making.