"We are setting out the schedule," said a spokesman for the Federal Motor Transportation Authority on Thursday.
At the start of October Volkswagen handed authorities its own plan for refitting cars that had been equipped with a defeat device – a software program which sidesteps emissions testing – which would have seen the coompany start to recall cars in January.
But the government has now definitively rejected the VW scheme.
The car company has been handed a deadline for fixing its cars, reports Spiegel, although what this is remains unclear.
Volkswagen has admitted to installing the defeat device in over 11 million cars worldwide.