The Tanzanian authorities have banned all domestic broadcasters from carrying foreign-made content without permission from the government.
International broadcasters, including the BBC, can currently be seen and heard on local radio and TV.
Rights groups say the Tanzanian authorities have in recent years become increasingly intolerant of criticism.
Publications have been banned and journalists imprisoned.
Correspondents say with elections due in October the new regulations will raise further questions about the state of democracy and free speech in Tanzania.