The NSW Independent Commission Against Corruption has announced public hearings into long-standing allegations of wrongdoing involving members of the state Liberal branch.
The hearings will launch on July 27 after the integrity watchdog began investigations under Operation Rosny.
The probe was sparked when state Liberal MP Ray Williams in 2022 used parliamentary privilege to claim powerbrokers within his own party were engaged in branch-stacking and improper local council dealings.
Controversial property developer Jean Nassif was alleged to have drawn on his political connections through donations to facilitate favourable planning decisions.
The claims led to a parliamentary inquiry in 2023 that engaged professional process servers to search for then-Liberal premier Dominic Perrottet's brothers, Jean-Claude and Charles, without success.
The inquiry took place months before NSW state elections, which culminated in now-Labor Premier Chris Minns unseating Mr Perrottet.
The commission's probe will scrutinise political donations by other figures, including Catholic Schools NSW chief executive Dallas McInerney and hotelier Michael O'Hara, between 2019 and 2023.
The anti-corruption body will also assess whether political donations from Nassif and his development company Toplace were accepted by Liberal Party members between 2020 and 2023 in return for outcomes he was seeking at the Hills Shire Council.
Developers are banned from making political donations
Mr Nassif allegedly sought to damage the reputation of former police minister David Elliott and gain the removal of then-building commissioner David Chandler.
A NSW Liberals spokesperson told AAP it would not be appropriate to comment on a current active ICAC inquiry.
But they noted the party "expects its members to meet the high standards demanded by this organisation, our membership and the public''.
Operation Rosny is also investigating a third allegation involving another Sydney council but, in this instance, the conduct of two Labor councillors is being probed.
The inquiry will assess whether former and current Strathfield councillors Sharangan Maheswaran and Karen Pensabene engaged in "dishonest" conduct towards fellow independent councillor Matthew Blackmore.
Mr Maheswaran was a former executive at Mr Nassif's collapsed company and had his devices seized by Australian Border Force officials in March 2023, days after police raided Mr Nassif's home and office.
NSW Treasurer Daniel Mookhey said he respected the commission, while refusing to be drawn on how the fallout would further damage the Liberals.
"We're not seeking partisan advantage out of this," he told reporters.
"We respect ICAC, we respect its independence ... but we support the ICAC because it's tough on us."
Nassif, formerly a high-profile developer, left Australia for Lebanon in 2022 but is being pursued by NSW Police after a two-year fraud investigation.
A warrant has been issued for his arrest, while 57 companies linked with Toplace are in administration.
AAP is seeking comment from those named in the probe.
The inquiry is due to run for eight weeks.