"The recall for Passats was planned for the ninth calendar week and to date our vehicles are still undergoing checks at the Federal Motor Transport Authority (KBA)," a VW spokesman told AFP, referring to a VW car model.
"The KBA is still not completely satisfied with some measures and requiring new information," said a spokesman, adding that it was hoping that the recall approval could come "in coming weeks".
VW has so far also failed to obtain an approval for the recall of its popular Golf models.
Volkswagen was forced to recall vehicles around the world after it admitted it had installed so-called "defeat devices" aimed at cheating emissions tests into 11 million diesel engines worldwide.
In Europe alone, some 8.5 million vehicles are to due to be sent back to workshops.
VW has set aside €16.2 billion to meet the heavy cost of repairs, as well as of regulatory fines and lawsuits, sinking it into a bottom-line loss of €1.58 billion euros in 2015, its first loss since 1993.