Poland's prime minister says she expects an apology from the head of the European Parliament for saying political developments under her new right-wing government are like a "coup d'etat."

Martin Schulz, who is German, told Germany's Deutschlandfunk radio Monday that "What is happening in Poland has the character of a coup d'etat and is dramatic. I assume that this week or in January at the latest we will have to discuss this extensively in the European Parliament."

He was referring to developments under the ruling Law and Justice party, which won a parliamentary majority in an October election and now aims to increase influence over the Constitutional Tribunal in a way critics say is undemocratic.

Prime Minister Beata Szydlo said Schulz's words are "unacceptable" and she expects an apology.