Tony Abbott will urge grassroots Liberal members to fight growing factionalism within the party at a meeting on Saturday.
The push comes as colleagues warn the former prime minister risks damaging his credibility by criticising government policy and "rewriting history".
Mr Abbott will be joined by assistant minister Angus Taylor at a forum in Sydney, which is being held in the lead-up to a convention on July 21-23, to discuss changes to the way candidates are preselected and senior positions are filled.
Reformers fear the NSW Liberals have been taken over by factions and lobbyists.
Mr Abbott, who represents the northern Sydney seat of Warringah, is promoting what is being called the "Warringah one member one vote motion".
It proposes to axe the existing "delegate" system where representatives of local Liberal branches and other internal bodies choose candidates.
Instead, all financial Liberal Party members of two years standing would be able to vote in a plebiscite within their electorate, with a reduced proportion of randomly selected outsiders involved.
"This has the effect of weakening factions within the Liberal Party due to the sheer logistics of exerting influence over a larger number of people," according to notes attached to the motion.
A second part of the motion extends voting rights to ordinary members for bodies such as the state executive.
Lobbyists, MPs and people closely associated with them would be banned from being on the party's state executive.
NSW Premier Gladys Berejiklian is understood to be seeking a watered down version of the motion, which would exempt sitting MPs from facing challenges under new rules.
However, supporters of the Warringah motion say they won't accept any compromise and anything less would lead to more Liberal members and supporters walking away from the party.
"It's so easy to get those people back - all they have to do is take the party away from the factions and lobbyists and give it back to the members and they will come back in droves," one member told AAP.
The meeting comes as senior Liberals queried Mr Abbott's recent outspokenness on issues ranging from the government's submarine project to climate policy.
Liberal frontbencher Concetta Fierravanti-Wells said Mr Abbott carried a certain responsibility as a former PM.
"If now he says that he was wrong when he was prime minister, well that's a matter for him, but he had the opportunity to do a lot of things," she said.
"But I would urge Tony not to try and rewrite history, because all it's doing is damaging his credibility."
Labor frontbencher Anthony Albanese said Mr Abbott had "gone nuclear" on the Liberals' moderate faction, whose most vocal proponent is cabinet minister Christopher Pyne.
"This is fight club. This is Manny Pacquiao out there versus (Jeff) Horn," he said.
