It cited sources it did not identify as saying the meeting on Saturday would be attended by a dozen or so key conservative politicians from across Europe.
These will include Hungarian leader Viktor Orban, Santiago Abascal from Spain's Vox grouping, and Matteo Salvini, the leader of Italy’s rightist League party, the Polish news agency reported.
Poland's Prime Minister Mateusz Morawiecki is also set to take part in the gathering, PAP reported.
According to one source quoted by the news agency, the meeting "will represent another step towards creating a wider platform of cooperation for Europe's conservative and rightist parties," and "everyone hopes it will lead to something bigger, perhaps in the next European Parliament."
Exploring the future of Europe
Kaczyński is set to deliver a keynote address at 10 a.m. on Saturday, followed by two behind-closed-doors sessions, featuring party leaders and their delegations.
The sessions will discuss the future of Europe and the EU, possible institutional reforms of the bloc and how the parties can work together going forward, PAP reported.
Finally, the conservative leaders are expected to issue a joint declaration, according to the news agency.
In a previous initiative, Poland's Kaczyński in July signed a statement with several centre-right and conservative groupings represented in the European Parliament, according to media reports at the time.
The signatories included Orban, Abascal, Salvini and France's Marine Le Pen, on behalf of their parties, as well as groupings from Austria, Belgium, Bulgaria, Greece, Finland, Denmark, Estonia, the Netherlands, Lithuania and Romania, according to PAP.
They called for a comprehensive, “back-to-basics” reform of the EU, with a sovereign role for European nations, arguing that people’s trust in the bloc’s institutions was being undermined by “a reinterpretation of the Treaties,” PAP reported at the time.
Meanwhile, in 2019, Salvini said Warsaw and Rome would be key to "a new spring" in Europe, news agencies reported.