Bitterly disappointed State Nationals leader Andrew Stoner accused federal Liberals of undermining their campaign to regain the seat.

The Nationals lost it in 2002 after sitting party member Rob Oakeshott left the party and held onto the seat as an independent until he won the federal seat of Lyne last month.

Independent Peter Besseling claimed victory last night after the Nationals' Leslie Williams, a nurse at Port Macquarie Base Hospital, conceded defeat about 9pm.

Mr Stoner said state Liberals leader Barry O'Farrell had done a good job but he lashed out at rogue elements inside the Coalition.

Mr Besseling has faced accusations of being backed by the Liberal Party and receiving assistance from the federal Liberal MP for Hume, Alby Schultz, in handing out how-to-vote cards.

It is understood prominent local Liberal Ken Dodds and the maverick Liberal senator Bill Heffernan were fingered by the Nationals for supporting the independent.

"I have a message for the rogue element in the Liberal Party - 'united we stand, divided we fall,"' Mr Stoner said last night.

"I don't want to see the Coalition fall short at the next state election because we are attacking each other. We need unity in the Coalition."

Mr Besseling, a former Waratahs second-rower and 1999 Ken Catchpole Medallist, has worked as a political adviser for his sometime rugby teammate Mr Oakeshott for the past three years.

He was upbeat after voting at St Joseph's High School in Port Macquarie.

"Put it this way, the electorate got $345 million in the last budget under an independent member."