BERLIN (Reuters) - Germany could deport as many as 26,500 migrants in 2016, more than in any year since 2003, a newspaper said on Thursday, citing federal police documents.

Chancellor Angela Merkel, who faces a national election next year, has been criticized for her open door refugee policy after an influx of more than a million people over the past year. She has emphasized the need to accelerate the deportation of migrants who have been denied asylum.

The Rheinische Post newspaper reported that 19,914 people had been deported by the end of September, almost three-quarters of them to the western Balkans.

A total of 20,888 people were deported in all of 2015, the newspaper said.

(Reporting by Andrea Shalal; Editing by Robin Pomeroy)