"Moreover, Google will operate with virtually no legal obligation to ensure the privacy, security, and accuracy of the personal data that it collects."
The complaint was filed by the Electronic Privacy Information Center along with the Center for Digital Democracy and the US Public Interest Research Group, all of which are involved in online privacy issues.
The groups said both companies have shown shortcomings in privacy issues that raise questions about the 3.1-billion-dollar takeover announced by Google earlier this week.
The complaint said the deal poses risks for Internet users in the US and worldwide.
"The acquisition of DoubleClick will permit Google to track both a person's Internet searches and a person's web site visits," it said.
"This could impact the privacy interests of 233 million Internet users in North America, 314 million Internet users in Europe, and more than 1.1 billion Internet users around the world."
DoubleClick said meanwhile that some reports "have incorrectly suggested that data collected by the company's online display advertising technology could be used by Google, or combined with information owned by Google. This is simply not the case."
DoubleClick said Google "would not be able to match its search data to the data collected by DoubleClick," because of contractual restrictions.
The complaint noted that the FTC had previously cited DoubleClick for its use of "web bugs" or "cookies" to track users' progress within websites and collect information about the user.
They also noted that Google stores its users' search terms in a way that can identify them through their IP address.
Because this practice is poorly disclosed, the groups said "Google's representations concerning its data retention practices were, and are, deceptive practices."
Both DoubleClick and Google, along with many other Internet firms, use files called "cookies" that are installed when an Internet user visits a web page, clicks on an ad or logs into a website.
Companies say this simplifies browsing for users who repeatedly visit certain websites, but it also allows browsing habits to be tracked back to the individual computer or user.
Google said last month it would begin routinely purging its data banks of information that identifies search engine users in order to better shield their anonymity.
In related news, Google announced that it plans to offer an expanded version of its Search History offering, which would track and store the Web pages users visit.
The idea is to offer users the ability to easily track web pages that had visited online in the past. In addition, Web History would allow Google personalize search results based on what users had searched in the past.
Although the feature will be disabled by default, it would allow Google to learn all sort of details about its users, data valuable for its advertising business.