Did NSW Labor’s safest seat just become a One Nation battleground?

Opposition Leader Kellie Sloane has lost yet another frontbencher months out from the next election, while Premier Chris Minns has been rocked by the prospect of having a safe seat turn into a battleground.

Veteran Liberal MP Mark Coure announced he would not recontest the key marginal seat of Oatley, joining fellow frontbenchers James Griffin and Alister Henskens in leaving parliament at the next election.

The surprise decision means the party will lose one of its key moderates and senior members of shadow cabinet, who withstood successive campaigns from Labor to take his marginal electorate since he first entered parliament in 2011.

Coure did not respond to requests for comment.

The decision comes as Minns repeatedly urged veteran Wallsend MP Sonia Hornery to recontest her seat for a sixth time, leaving NSW Labor facing the prospect of its safest seat in parliament becoming an overnight battleground against One Nation.

Hornery, the popular local member of the electorate in Newcastle’s western suburbs, announced on Tuesday that she would retire at the March election after 20 years in parliament.

Gavin Morris, the independent lord mayor of Newcastle who many consider Hornery’s possible replacement, will meet the Wallsend MP to consider whether he will run at the March election. If so, it would be as an independent.

“This [the lord mayoralty] is my focus. There’s still lots of work to be done,” he told the Herald.

First elected in 2007, Hornery, 64, has repeatedly increased her margin after being one of only two MPs in the Hunter to survive the 2011 wipeout under Kristina Keneally. The seat is now Labor’s safest in parliament, with a 31.8 per cent margin.

Despite the imposing margin, Hornery’s local popularity means her retirement immediately puts the seat in frame for One Nation. Wallsend encompasses the western suburbs of Newcastle as well as the outskirts of Maitland to the north.

It also borders Cessnock, the long-time Labor stronghold which the party is increasingly resigned to losing.

“Over the past 20 years the Wallsend community has experienced both great and difficult times,” Hornery said.

“I thank the many people and organisations who have supported me and offered their friendship over the years. I’m so proud of our community and it’s been a privilege being the local member.”

Hornery follows Aboriginal Affairs and Treaty minister David Harris, who announced earlier this week he would exit politics at the March election after 11 years as the member for the Central Coast electorate of Wyong.

The spate of retirements comes as both parties confront the potential impact of One Nation at next year’s poll. NSW Labor officials have warned MPs the party could lose more than a dozen seats and be bundled out of government in one term during a series of closed-door briefings to ram home the threat posed by One Nation at the March election.

While Cessnock has long been identified as the most at-risk Labor seat, electorates including Camden, Maitland, Port Stephens, Bega, South Coast, Swansea, Penrith, Kiama, The Entrance and Shellharbour are among those party officials are concerned about.

A One Nation source, speaking anonymously to canvass party deliberations, said they now believed Wallsend was in play for them.

The Liberals, meanwhile, are confronting broad issues across Sydney, with 10 of the party’s electorates held on less than a 5 per cent margin. They will now have to defend two of those seats – Manly and Oatley – without longstanding MPs.

In Henskens’ seat of Wahroonga, John Foong, who was Domain’s chief commercial officer and managing director until last year, won a preselection against a crowded field, winning 55 votes compared to 22 for his closest challenger, Tim Sowden, an insurance executive.

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