"Around 50" Volkswagen employees have come forward just ahead of the deadline to testify in the group's internal investigation into the emissions controls cheating scandal, a spokesman has said. 

Employees had been given until Monday to come forward to testify without fear of repercussions on the part of VW, news agency AFP noted. 

The company has said the revelations have had an impact on car sales, with demand for the group's 12 brands falling. US sales plunged 25% in November, to 23,882 units, down nearly 8,000 from a year earlier but new car registrations in Germany rose 9% in November to 272,000, according to VDA.

November year to date registrations rose 5% to 2.959m and VDA forecast a 5% rise to 3.17m for full year 2015 and 3.2m in 2016"if the framework conditions do not deteriorate". Federation chief Matthias Wissmann told AFP the VW scandal had undermined confidence in the automobile sector but should not have too many repercussions on sales nor would discredit diesel technology in general.