Lower Saxony's prime minister Christian Wulff has demanded that the families controlling Porsche settle their differences and decide on whether to seek an integration with Volkswagen or not.

Wulff urged the Piech and Porsche families to decide on the future of Porsche and its larger rival Volkswagen before the celebration of the 100th anniversary of VW's subsidiary Audi, which will take place on 16 July, Financial Times Deutschland reported. Debt-ridden Porsche currently holds a stake of around 51% of VW.

The premier asked the families to bring the continuous public debate to an end. The owners had all the necessary facts, so they could take up a clear stance on the matter in the next few days, Wulff said.

Wulff rejected reports suggesting Volkswagen had improved its offer to Porsche and was willing to buy 50% in the sports car maker for EUR 4 billion.

Lower Saxony is VW's second-largest shareholder after Porsche. Wulff himself is a member of VW's supervisory board.

In a commentary, the paper said Ferdinand Piech, Volkswagen patriarch and Porsche heir, seemed to be emerging as a winner in the VW-Porsche dispute, thanks to his Machiavellian techniques.

The traditional virtues like honesty, justice or modesty were never Piech's forte when it comes to management, the paper said. The chairman of VW's supervisory board is as talented in power plays, as he is in engineering cars. He is characterised by his cleverness and aloofness, and is one of the few masters of intrigue in the economy.

The all too blunt Porsche's CEO Wendelin Wiedeking has a lot to learn from his nemesis Piech. Wiedeking tried to have his smaller company swallow the giant VW and thus burdened Porsche with debts for billions of euros. The plan backfired spectacularly and now VW is threatening to acquire the small sports car maker.

In the mean time, Wiedeking's attempts to take over VW and his brash style earned him the criticism of the VW patriarch, who recently panned the CEO with vitriolic remarks while at a dinner in Sardinia. The grandson of Ferdinand Porsche is using the turbulence on the markets to create an unprecedented automotive empire, FTD said. If Wiedeking's coup fails, he will have to submit to Piech.