The chairman of German auto parts supplier Robert Bosch warned on Thursday of declining revenue in the coming year, and said he cannot rule out further job cuts in Germany in addition to the 7,000 it has already announced.

The announcement, made in an interview with chairman Stefan Hartung published by Der Tagesspiegel newspaper on Thursday, adds to the gathering gloom in the auto industry that underpins Europe's largest economy.

Profit at Volkswagen plunged to a three-year low in the third quarter, Europe's largest carmaker said on Wednesday, and workers are threatening to strike over VW's plans to lower costs by closing plants in Germany and cutting pay.

Hartung said Bosch's turnover would come in slightly below last year's 92 billion euros, while return on sales, which it had wanted to grow by two percentage points more than last year's 5%, would come in at 4% at most, he said.

"I cannot rule out that we will have to further adjust personnel capacities," Hartung said, calling on the government to do more to support industry.