The Facebook administration has confirmed that site data indicates it has been blocked in Nauru despite denials from the Nauru government.
Last week the government announced it was blocking pornography sites, prompting opposition claims it had shut down Facebook.
The government denies this but concedes some social media sites may have been blocked temporarily.
In a statement this morning Facebook says it has been aware of the issue since Friday.
" We believe that restricting access to a free and open internet deprives people of important economic and social opportunities and choices and hope that access will be restored soon."