Germany and Turkey discussed ways to revive their business ties on Monday after a period of strain in recent months.

Turkish Economy Minister Nihat Zeybekçi, speaking after meeting her German counterpart Brigitte Zypries, said that bilateral trade volume could double to 70 billion euros a year.

"That shows how much potential we have," he said.

Given the current trade volume and investments totaling 12 billion euros, Zypries said Germany was Turkey's most important business partner and Berlin was keen to expand business ties.

Germany asked Ankara to set reliable framework conditions to facilitate continued investment by German companies in Turkey.

"We need clear assurances about the legal securities," Zypries said. "The rule of law is a central requirement for the German government and German industry. Companies need reliable framework conditions to make investment decisions."

She told reporters that a joint economic commission was due to meet around the end of the year, and a German-Turkish energy forum was also to be reactivated.

Relations between the two countries plunged recently after German local authorities cancelled several events related to Turkey's April 16 referendum on constitutional change that Turkish government ministers had planned to address.

Nearly 3 million Turkish migrants live in Germany and around half are eligible to vote.