One of these areas appears to be Phuket. Many people in Thailand are "tweeting" across Twitter about the access problem.
Many users are having problems accessing the site on desktops and smartphones, although it is accessible via proxy.
A spokesman for the National Council for Peace and Order told The Phuket News this afternoon that the NCPO has blocked some politically-oriented pages on Facebook, but not the entire system.
He said that people should be able to access their own accounts.
Social media users across the country have not been able to access the site since 3pm. According to telecommunications sources, about 30 million Facebook accounts have been blocked.
Additional reporting by The Bangkok Post.