Former Liberal candidate Brooke Vitnell has told party members she will not contest the upcoming Paterson election.
Ms Vitnell secured a 1.7-point swing against Labor incumbent Meryl Swanson in 2022 but has opted to focus on her family and her Medowie law firm.
She and her husband, former federal government media director and strategist Julian Leembruggen, have a seven-month-old daughter.
"It is not the right time for my young family and my burgeoning law firm," Ms Vitnell said.
"I've started getting calls and emails from members of the community asking how they can support my campaign, and I felt to clear the air early with them.
"I look forward to supporting a strong local candidate for the Liberal party for Paterson."
She told members about her decision on Monday night, opening up what could be a lively preselection contest.
Party sources said Maitland councillor Ben Mitchell and Laurence Antcliff could throw their hats in the ring.
One source said Mr Mitchell had nominated in 2022 for the NSW upper house seat vacated by Catherine Cusack but had withdrawn before Aileen MacDonald filled the seat.
Ms Vitnell cut Ms Swanson's electoral margin to 3.3 points in 2022, defying a 3.7-point swing to Labor nationally.
A looming boundary redraw could turn Paterson into a nominal Liberal seat.
The Liberals' submission on the boundary redistribution called on the Australian Electoral Commission to remove working-class Kurri Kurri from Paterson and include the more conservative areas of Hawks Nest, Tea Gardens, Lorn, Bolwarra and Largs in the division.
The Liberals held Paterson through long-time member Bob Baldwin before a redistribution in 2016 shifted the coalfields towns of Maitland and Kurri Kurri into the electorate and delivered Labor a 10.5 per cent swing.
The AEC is due to publish the proposed boundary changes in late May or early June.
Ms Vitnell is a former Baldwin staffer who also has been employed as an adviser by federal MPs Steven Ciobo, Michaelia Cash and Concetta Fierravanti-Wells.
Ms Swanson won 7609 more votes after preferences than her Liberal challenger in 2022.
Liberal nominations for local government elections in Cessnock and Lake Macquarie closed on Monday, but the party has not announced a nomination period for Maitland.
Liberal nominations close in Newcastle and Port Stephens on May 20.