Deutsche Bank CEO Josef Ackermann has told Porsche's owner families of the urgency to stump up cash in order to pay down the company's debts, which have risen to 14 billion euros (20 billion pounds), a German magazine said on Saturday.

Ackermann himself told Porsche supervisory board chairman Wolfgang Porsche that a mere capital increase from the Porsche and Piech families would not be sufficient to pay for the carmaker's financial obligations, a pre-release of Der Spiegel said, citing banking sources.

The debts include some bonds that needed to be paid, it added.

Porsche on Thursday agreed it would increase its capital by at least 5 billion euros ahead of a planned integration with Volkswagen .

A Porsche spokesman told Reuters he could not confirm the 14 billion euros figure.

He said Porsche's net debts total around 10 billion euros. In January, the total was around 9 billion euros.

(Reporting by Marilyn Gerlach; editing by James Jukwey)