“The unreported figure of people doing it is enormously high, certainly in the tens of thousands,” said head of the traffic branch of the Berlin police, Andreas Tschisch.
He said that the police did not have the resources to control the number of people who were reaching to answer a text or Facebook message while driving.
It could be very difficult to tell when someone was reading a message, as smartphones can be held inconspicuously, he said.
A spokesman for the North-Rhine Westphalia (NRW) interior ministry said there were no concrete numbers on those using their phone at the wheel.
Mobiles have become such an integrated part of life that people were finding it harder not to use them for stretches of time – despite knowing the dangers of driving with them, the spokesman added.
Last year around 131,000 people were caught on their phones in NRW. Drivers can be fined €40 for using their phone and given points on their licence.