The country has announced that it is officially banning Facebook, Twitter, YouTube and all South Korean sites.
The Ministry of Posts and Telecommunications made the announcement this week in a move to highlight its worry over the spread of online information.
Although few North Koreans have internet access, with some able to access a government-sanctioned intranet, foreigners had previously been able to browse with little restriction.
The move will inevitably make it more difficult to spread information about the country to the outside world.
The government is also banning gambling and "sex and adult" websites over a "certain period of time" (via The AP).
Facebook and Twitter have been informally banned for a while, but the new statement says that anyone who tries to hack these sites, access them in an "improper" way or distribute "anti-republic data" will be punished.
There are similar restrictions in neighbouring China, which bans sites that it considers politically sensitive.
Source: Digital Spy