Several powerbrokers in the NSW Liberal party have been asked to resign from its state council, in the latest push to remove professional lobbyists from positions of influence.

NSW Liberal state director Chris Stone wrote to representatives of Liberal-aligned firms who are also state council delegates shortly after former prime minister Tony Abbott complained about conflicts of interest during an interview with ABC TV's Four Corners.

The request has been sent to left faction powerbroker Michael Photios and centre right faction boss Nick Campbell, who jointly own lobbying firms PremierState and CapitalHill Advisory.

Joseph Tannous, the owner of lobbying firm 1st State, and the company's special counsel, former Senator John Tierney, have also been asked to resign as delegates, as has Matt Hingerty, the managing director of Barton Deakin.

The 750 delegates to the NSW Liberal state council participate in preselection decisions and elect the party's ruling state executive.

Upon becoming prime minister in 2013, Mr Abbott banned party officials from lobbying his government. Then NSW premier Barry O'Farrell introduced the same rule for his government.

The announcements saw Mr Photios and Mr Tannous quit their positions on the NSW Liberal state executive but remain state council delegates as they are entitled to.

In March, Mr Photios and Mr Campbell became involved in the Liberal Party preselection for NSW senate candidates after state executive members on the selection panel, Julian Leeserand Mich­elle Bishop, nominated them as their proxies.

During his Four Corners interview, Mr Abbott renewed his attack on lobbyists holding positions of influence in the Liberal Party.

"A lobbyist is someone who makes money out of getting people in front of politicians," he said.

"A powerbroker is someone who controls or influences the preselections of those politicians. 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 that we should have inside the Liberal Party."

Mr Stone wrote to the lobbyists several days later and after it emerged that former federal MP Michael Baume had asked NSW electoral authorities whether Mr Photios and Mr Campbell breached the lobbyist code of conduct by participating in the Senate preselection.

Mr Photios declined to comment.

Mr Hingerty confirmed he had resigned from state council. "I'd always been uncertain about the state council issue and I'm happy that the party has clarified that," he said.

"Our position at Barton Deakin is that the party regulates and we will comply."

Mr Tannous, Mr Campbell and Mr Tierney did not respond to requests for comment.

It is understood the view of some is that Mr Stone's request is an unconstitutional constraint on participation in the Liberal Party as they do not believe state council is a management body.