A German gynecologist is being investigated by police after secretly taking 35,000 pictures of female patients naked inside his practice.

So far 700 victims have filed criminal complaints against the 56-year-old doctor, who practised in the small town of Schifferstadt, in Rhineland-Palatinate in the west of the country.

"We are still in the middle of the investigation, it may well be that more victims come forwards," Lothar Liebig, the director of public prosecutions in Frankenthal, told the German tabloid Bild.

Approximately 3,000 women were unknowingly snapped by the perverted doctor while undergoing clinical examinations, the report said.

The doctor no longer practises, and could face up to one year in prison.