BERLIN (Reuters) - German Justice Minister Heiko Maas appealed in a newspaper interview to media to hand over the Panama Papers that show how offshore firms are used to stash the wealth of the world’s elite.

German Justice Minister Heiko Maas attends a cabinet meeting at the Chancellery in Berlin, Germany, April 6, 2016. REUTERS/Fabrizio Bensch

Governments around the globe have started investigating possible financial wrongdoing by the world’s rich and powerful since details of hundreds of thousands of clients were leaked from Panama-based law firm Mossack Fonseca, which has set up around 250,000 companies in the last four decades.

The scandal broke when an investigation was published last Sunday, with German newspaper Sueddeutsche Zeitung saying it had received a cache of 11.5 million leaked documents from Mossack Fonseca and then shared them with more than 100 other international news outlets and the International Consortium of Investigative Journalists (ICIJ).

Maas told German newspaper Tagesspiegel that tax investigators and lawyers in Germany were carefully looking at all clues related to reports on the Panama Papers and several investigations were already underway.

“It would help bring about justice if important documents were handed over to the authorities,” he said, adding that this would also boost revenues for state coffers.

He said he was optimistic that investigating authorities and the media would together find a way to at least exchange “certain valuable information”.

On Friday a spokeswoman for the German finance ministry said the government had taken note of comments from media that they did not want to hand over documents, adding that the media had the right not to.

On how to tackle offshore firms, Maas said if international pressure did not suffice to end “criminal manipulation”, Germany would need to consider further national measures.

“We should take up an important suggestion from former chancellor Helmut Schmidt to prohibit financial deposits that benefit these firms and people who are legally registered in tax and supervisory havens,” he said.

He said Germany had long been working on a proposal to make firms and banks more liable and added that higher and more effective sanctions were needed. Big firms need to feel the effect of such sanctions too, he said, adding that he would make a concrete proposal on that this year.