Poland's ruling right-wing Law and Justice party lost its majority in parliament on Wednesday after a small coalition partner left over concerns about media legislation.
Prime Minister Mateusz Morawiecki kicked the head of the Agreement party, Jaroslaw Gowin, a deputy prime minister, out of the government on Tuesday.
The party said on Wednesday that it would leave the governing coalition.
The parties' dispute is over legislation that would prevent non-European owners from having a controlling stake in Polish media companies.
The proposed legislation is widely viewed as an effort to silence an independent, US-owned television broadcaster that is critical of the government. A vote is expected later on Wednesday.
It would push American company Discovery Inc. to sell its controlling stake in TVN, a network with many channels that operates Poland's all-news station TVN24 and has a flagship evening news program watched daily by millions.
The Law and Justice Party appeared poised to pick up some votes from opposition lawmakers, including some from Confederation, a small party made up of libertarian and nationalist politicians.