Canada's privacy commissioner has started a second investigation into social networking site Facebook.
The fresh probe is in response to a series of complaints about the privacy policies of the site.
The complaint concerns a tool that Facebook introduced in late 2009 that makes users of the site review their privacy settings.
The complaint alleges that the tool makes it harder for Facebook users to manage who sees personal information.
"Some Facebook users are disappointed by certain changes being made to the site - changes that were supposed to strengthen their privacy and the protection of their personal information," said Elizabeth Denham, Canadian assistant privacy commissioner.
The changes to privacy settings that Facebook introduced in December 2009 were partly in response to an investigation by Canada's information commissioner into how the site treats personal data.
Following its initial investigation the Canadian commissioner said Facebook should give members more control over who can see and search for status updates and details such as birthday dates.
The information commissioner said some people feel the changes Facebook has made made key data "even more exposed now than before".
In response, Facebook said the changes it had introduced were easy to understand and lawful. It added that it had made unprecedented efforts to educate users about the changes and their consequences.
"Any recommended changes to a user's privacy settings were clearly shown to the user repeatedly and were not implemented until the user accepted these changes," said Barry Schnitt, Facebook spokesman.
"Users were required to review the final settings after any changes and pointed to where they could reverse or further customize their settings," he added.
In the US, Facebook faces action from the Electronic Privacy Information Center which has filed a complaint about the changes to the Federal Trade Commission.