“It’s important to the president that state media be impartial, objective and credible,” presidential spokeswoman Malgorzata Sadurska told reporters on Thursday.
“That’s why the president signed into law the radio and television bill” that the conservative-dominated parliament approved late last month.
Under the new law, senior figures in public radio and television will be appointed — and sacked — by the treasury minister, and no longer hired by the National Broadcasting Council.
The new legislation will also see the current managers and supervisory board members of Poland’s public broadcasters fired with immediate effect.
The ruling Law and Justice (PiS) party had earlier said it plans to turn the PAP news agency and public television and radio — all currently state-owned businesses — into national cultural institutions like the opera or the national museum.
The media measure is the latest controversial legislation introduced by the PiS, which is led by former premier Jaroslaw Kaczynski and which won a general election in October after eight years in opposition.
Duda already passed into law late last year a reform of the constitutional court, despite mass protests and claims by the opposition that the changes threaten judicial independence.
The Council of Europe, the continent’s top human rights watchdog, had urged Duda against signing the media law.
The Polish government’s legal moves have prompted escalating warnings from the European Commission that it could intervene, including two letters from its vice president, Frans Timmermans, asking Warsaw for information.
In an unprecedented move, the Commission is set to debate the state of rule of law in Poland on January 13, which could lead to a potentially punitive process aimed at buttressing democracy and rights in the 28 EU states.