The New South Wales Liberal Party has asked a number of key powerbrokers to resign from its state council as it moves to reduce the influence of lobbyists.

The request, from Liberal Party state director Chris Stone, came after former Prime Minister Tony Abbott launched a scathing attack on lobbyists on the ABC's Four Corners program, branding them "factional warlords" who created "the potential for corruption."

Moderate faction powerbroker Michael Photios and Nick Campbell from the centre right faction, who jointly own lobbying firms Premier State and CapitalHill Advisory, were among those to receive letters from Mr Stone asking them to resign as delegates.

The owner of lobbying firm 1st State, Joseph Tannous, and the company's special counsel, former senator John Teirney, as well as the manager of Barton Deakin, Matt Hingerty, were also sent the same request.

The ABC is contacting the lobbyists for comment.

The Liberal state council has 750 delegates who take part in preselection decisions and elect the party's state executive.

Last month, Mr Abbott told Four Corners he was concerned about the power that lobbyists wielded on preselections and the potential for conflicts of interest.

"If you are making money out of the people whose preselections you control or influence there is obviously a potential for corruption, and that's the last thing we should have inside the Liberal Party," Mr Abbott said.

He called for the party to boost its membership in order the reduce the ability of factional bosses to control preselections.

"Some of these factional warlords have a commercial interest in dealing with politicians, whose preselections they can influence... the best way to see off the factionalists is to open up the party," he said.

Trent Zimmerman has defended lobbyists within the NSW Liberal Party. ( ABC News: Ursula Malone, file photo )

In response to Mr Abbott's comments, NSW Liberal Party president Trent Zimmerman defended lobbyists and denied that one or two people had extraordinary influence over its affairs.

"I think people occasionally make claims like that to try and demonise those that they might see as on the other side of the internal fence in the Liberal Party," Mr Zimmerman said.

"But I'm yet to see anyone actually demonstrate to me where that conflict has arisen or is likely to arise."

As prime minister, Mr Abbott banned party officials from lobbying his government, and Barry O'Farrell introduced a similar ban when he was the NSW premier.