BERLIN (Reuters) - Britons' vote to leave the European Union is already affecting German exports to Britain and a drop in sterling, which hit a 31-year low on Friday, is making things worse, Germany's DIHK Chambers of Industry and Commerce has said.

"Brexit is already weighing on the German economy," DIHK managing director Martin Wansleben told German daily Welt after the chambers of commerce surveyed 5,600 German firms.

"Faced with the decline of the British pound, German products in the (United) Kingdom will be much more expensive, and our export growth to the UK will also fall below zero this year," Wansleben added.

The DIHK survey also showed German businesses were losing their appetite to invest in Britain. Wansleben said that until there was clarity on how Brexit would unfold, Britain would be "unattractive as a place for foreign businesses to invest."

In July, the DIHK said it saw a 1 percent drop in exports to the United Kingdom in 2016, down from a previous forecast of a 5 percent rise.

(Writing by Paul Carrel; Editing by Hugh Lawson)