Germany has been sending an increasing number of migrants back to Austria every day since the beginning of the month, Foreign Media reports.
Many had no valid documents, whilst others did not want to apply for asylum in Germany but in other countries, notably in Scandinavia, reportedly.
New Year's Eve attacks on women in Cologne, blamed on migrants, have put pressure on Chancellor Angela Merkel.
Most of those sent back to Austria are not Syrians, who usually get asylum.
Instead, they are migrants mostly from Afghanistan as well as Morocco and Algeria.