Jacob Kohnstamm, chairman of the College for the Protection of Personal Data, said that Google's combining of data from different services, including surfing multiple websites, to tailor ads and personalize services like YouTube "spins an invisible web of our personal information, without our permission, and that is outlawed."
In a statement, the watchdog said Google, "does not adequately inform users about the combining of their personal data from all these different services."
It added that consent, required by Dutch law, for the combining of personal data from different Google services "cannot be obtained by accepting general (privacy) terms of service."
Kohnstamm's organization said it has invited Google to a hearing, after which the watchdog will decide on possible enforcement action.
Verney said Google had "engaged fully" with the Dutch investigation and would continue to do so.
Spain's Data Protection Agency said in June that it had initiated sanction proceedings after initial investigations showed Google Spain and Google Inc. may be committing six infractions against the country's data protection law. It said the company could also face fines of up to 300,000 euros ($408,000).