The popular vote was proposed by outgoing head of state Bronisław Komorowski, following the first round of the presidential election on 10 May.

The referendum will ask three questions, on political funding, changes in the voting system and the principles governing tax law.

During a press conference, PM Kopacz said that PiS did not originally want the referendum. Now PiS deputy leader Beata Szydło has said that the party wants to widen the scope of the referendum slated for 6 September.

PiS proposes to add questions about lower the retirement age, the minimum schooling age (currently six years in Poland) and the limiting the selling of state-owned forests.

Beata Szydło was nominated by party leader Jarosław Kaczyński as the candidate for the post of Prime Minister in the autumn general election.

Material from Radio Polska.