The justice ministry, local councils, probation service and social workers are to store privacy-sensitive information about people suspected of being radical Muslims for up to five years under a new agreement, the NRC said on Wednesday.

The paper says the decision to hold the information is controversial because many of those involved have not been convicted of any crime. The police can already keep files about potential jihadis for five years and that right is now being extended to other institutions in the legal chain.

Officials say the change is necessary because the speed at which people become radicalised varies.

However, Leiden University terrorism expert Quirine Eijkman told the paper the move is a ‘serious breach’ of personal privacy. ‘As soon as someone thinks you are an extremist, all sorts of information about you is kept and stored,’ he said. ‘This is a disproportionate measure because it is very difficult to estimate when a radicalised person actually becomes a danger.’

The Dutch privacy watchdog Autoriteit Persoonsgegevens said it had not yet checked if the new move is in breach of privacy rules.