Rights group Privacy International rated the search giant as "hostile" to privacy in a report ranking web firms by how they handle personal data.
The group said Google was leading a "race to the bottom" among net firms many of whom had policies that did little to substantially protect users.
In response Google said the report was mistaken and that it worked hard to keep user data confidential.
The report by the veteran cyber rights group is the result of six months' research which scrutinised 20 popular net firms to find out how they handle the personal information users gave up when they started using such services.
None of the firms featured in the report got a "privacy friendly" rating...