The Liberal Party is often described as a ''broad church'' and a new appointment to its NSW executive is only set to reinforce the point.

The Hills Shire councillor Robyn Preston is set to join the powerful Liberal state executive following the announcement that powerbrokers Michael Photios and Joe Tannous will resign at the end of this month to run their lobbying businesses.

On the rise: Robyn Preston was appointed to the Liberal executive.

The resignations followed Prime Minister Tony Abbott's declaration that lobbyists would be banned from holding official positions in the Liberal Party under his watch.

Mr Photios owns the business Premier State, while Mr Tannous owns a firm called 1st State.