Polish President Andrzej Duda on Wednesday appointed Jaroslaw Kaczynski, the leader of Poland's ruling Law and Justice (PiS) party, as deputy prime minister of the government.

Kaczynski was deputy prime minister and head of the government's national security and defense affairs committee until June 2022 but resigned to focus on preparations for parliamentary elections later this year.

The return of Kaczynski, widely viewed as Poland's de-facto ruler, comes amid a stuttering campaign by PiS, for a third term that would likely see it continue policies that have set it at odds with the European Union (EU).

Although PiS is ahead in most opinion polls, a question mark remains over whether it can secure a parliamentary majority.

Opposition parties received a boost this month from a large anti-government march in Warsaw.

PiS faces rising anger over Poland's strict abortion laws and was strongly criticized for a decision to use images of Nazi Germany's Auschwitz death camp in a campaign video.

Divisions in the ruling coalition have also re-emerged over Poland's relations with Brussels, after the EU withheld funding over rule of law concerns.

Critics say PiS, since sweeping to power in 2015, has undermined the independence of Poland's courts, turned state media into an outlet for propaganda and stirred up discrimination against ethnic and sexual minorities.

PiS denies subverting any democratic rules and says its policies are aimed at preserving Polish traditions and at making the economy work in a fairer way for all Poles.

Its mix of conservative social values and generous social welfare programs has proved popular with many voters, propelling it to victory in two consecutive parliamentary elections.

(With input from Reuters)