A group of senior Law and Justice politicians, including party leader Jarosław Kaczyński and former prime minister, Mateusz Morawiecki, arrived at the headquarters of state-run TV broadcaster TVP on Wednesday afternoon.
They said the government's replacement of public media chiefs resembled a "coup d'etat" and an illegal "takeover by force."
Kaczyński told reporters Law and Justice stood in defence of democracy and "pluralistic media."
Some 90 Law and Justice politicians and supporters gathered in and outside TVP headquarters, the state news agency PAP reported.
Meanwhile, Culture Minister Bartłomiej Sienkiewicz told the Gazeta Wyborcza daily newspaper that the protest "will achieve nothing."
Deputy Prime Minister Krzysztof Gawkowski said Law and Justice politicians sought to "stop the changes" at the public TV broadcaster, which were designed to "depoliticise TVP and make it democratic."
Earlier in the day, the government announced that the culture minister had relieved the CEO's of TVP, Polish Radio and Polish Press Agency PAP of their duties, as well as dismissing the boards of directors of these outlets.
Sienkiewicz has also appointed new boards of directors for TVP, Polish Radio and PAP, which in turn have appointed new executive boards, the ministry of culture added in its statement.
It also said that the "necessity and justification" for the move flowed from Tuesday's resolution by the Polish parliament, which called on the government to "restore the impartiality and credibility of public media," private broadcaster Polsat News reported.
Source: PAP, Polsat News