Norwegian police have previously claimed that the website had refused them access to her account.
During a press briefing on the investigation into the missing girl, Oslo police inspector Hanne Kristin Rohde said investigators had "for the time being received a 'no' from Facebook regarding access and insight into her account."
She did not specify the reasons Facebook had given for the refusal, but said the social networking site had saved the content of the account and that police would submit a new request.
But Facebook told AFP in an emailed statement that the social networking site had been assisting police in the investigation.
"We've been cooperating with the police within a matter of minutes of them contacting us and are supplying them with further information relevant to the investigation," the statement said, without providing further details.
Sixteen-year-old Sigrid Giskegjerde Schjetne disappeared on her way home late Saturday.
Her shoes and mobile phone were found near a kindergarten on the route between her friend's house and her home. There were also witness reports of hearing screams around the time she was reported missing.
The case has engaged Oslo this week with hundreds of volunteers collecting each day to assist police in the search.