Sentiment among German exporters markedly worsened in September, with exports to all major regions in decline, according to a survey by the Ifo economic institute released on Tuesday.

The institute's export expectations indicator fell to minus 11.3 points in September, from minus 6.5 points in August.

"Germany's export economy is going through a weak phase," Klaus Wohlrabe, head of surveys at Ifo, said.

"It's likely that export demand won't pick up again significantly until next year," he added.

All sectors are facing a decline in foreign business, except for the manufacturers of leather goods, furniture and some companies in the food industry, the institute said in a statement. (Reporting by Amir Orusov, Editing by Rachel More)