The grouping's leader Jarosław Kaczyński and his deputy, former prime minister Mateusz Morawiecki, met for around three hours at PiS headquarters in Warsaw but failed to resolve a dispute over a leadership ultimatum requiring MPs to declare they have no ties to internal party associations.
The row centres on the Rozwój Plus (Development Plus) association founded by Morawiecki.
Party spokesman Rafał Bochenek described the talks as "constructive" but said they had not resolved the central issue.
According to Bochenek, Kaczyński offered a compromise: freezing, rather than dissolving, Rozwój Plus until the next parliamentary election, with its activities folded into the party.
He said the talks broke down partly because Morawiecki would not accept equal treatment for all MPs in the parliamentary group while seeking special conditions for himself.
Morawiecki's allies rejected the proposal.
PiS MEP Piotr Müller, a member of Rozwój Plus, said the plan to freeze the association and absorb its work into the party amounted "in practice" to shutting it down.
He said goodwill remained on their side and there was still time for an agreement, but ruled out signing "loyalty declarations" or being pressured into "humiliating statements."
Fellow MEP Waldemar Buda said Morawiecki had put forward several proposals, but that the continued existence of the association and the withdrawal of what he called "humiliating declarations" were non-negotiable.
Earlier on Thursday, PiS MP Jacek Sasin said around 150 MPs had already signed statements confirming they did not belong to associations engaged in "political activity" within the party.
Sasin also said his own association, Po pierwsze Polska ("Poland First"), had ceased operating, while Morawiecki indicated he intended to remain in PiS and continue developing Rozwój Plus.
Bochenek explained that Kaczyński himself had signed a standard membership form, as every party member does on joining – separate, he stressed, from the new statements at issue.
The deadline for MPs to submit the declarations passed at midnight on Thursday; Bochenek said they could be sent by email or WhatsApp.
Kaczyński is due to make a statement at PiS headquarters at midday on Friday.
(ał)
Source: PAP