NSW Liberals hit with MP exodus amid surge in popularity for One Nation

On Monday morning, New South Wales Opposition Leader Kellie Sloane oozed optimism.

"Watch this space, because I am getting more confident that we will be in government next year," she told 2GB's Ben Fordham.

"You'll be leading a government?" Fordham asked.

"Yes, I will be."

But the actions of some of her most experienced colleagues suggest they do not share that confidence, as the Coalition polls behind Labor and a surging One Nation.

On Tuesday, Mark Coure became the third Liberal frontbencher in less than three months to announce their retirement from parliament.

The shadow roads and south west Sydney minister said he would not run again for his southern Sydney seat of Oatley at the March election.

In September, two other members of shadow cabinet, Alister Henskens and James Griffin, announced their own departures from parliament.

So far, six Liberal MPs are not recontesting their seats, including backbenchers Mark Taylor, Ray Williams, and Tanya Davies.

All but Mr Taylor previously served as government ministers, and the loss of decades of experience is unhelpful to Sloane.

Mr Coure's retirement came as a surprise to both sides on Macquarie Street.

He had campaigned fiercely in recent days and weeks, including on proposed train timetable changes, which the government ultimately abandoned.

While he held Oatley by a wafer-thin 0.8 per cent against Labor, it always had been marginal for the veteran MP.

"I bucked the trend every election," Mr Coure told ABC Radio Sydney on Tuesday.

The 48-year-old denied that political risk was a factor in his decision, saying he wished to spend more time with his two young sons.

But he also said this: "To walk out undefeated is a feather in my cap."

The Liberals are unlikely to lose Oatley to One Nation, but the orange wave may help deliver it to Labor, thanks to optional preferential voting.

Unlike federal elections, and elections in other mainland states, the New South Wales ballot does not require voters to mark a preference beyond a '1' vote.

As former ABC election analyst Antony Green has pointed out, a switch of Liberal support to One Nation in seats like Oatley places Labor well to win by giving it the highest primary vote.

Labor has its own share of upcoming retirements, with Prospect MP Hugh McDermott, Wyong MP David Harris, and Wallsend MP Sonia Hornery all bowing out at the end of this term.

While Wallsend looks very safe for Labor on paper, with a 31.8 per cent margin, the party is worried the Hunter electorate could fall to One Nation.

Last week, Premier Chris Minns effectively wrote off the Coalition.

"By any poll, by any measure, [One Nation leader] Mike Newman will either be the premier or the opposition leader after the 13th of March," Minns told 2GB.

Mr Newman is the only lower house candidate One Nation has announced to date.

"We're in the thick of recruiting for all remaining 92 seats including Wallsend," Mr Newman told the ABC.

He said there were 900 candidates to process.

There is still a pathway for the Coalition to form government if both sides lose enough seats to One Nation, and One Nation fails to gain a majority.

If none can get there on its own, it will need to make a deal with another, and it seems unlikely One Nation would side with Labor.

Sloane alluded to that on Monday as she talked up the Coalition's chances of entering government next year.

"If it relies on the support of the crossbench, so be it. But everywhere I go, people are upset with Labor," Ms Sloane said.

But that prospect appears not to have been enough to convince at least some of her soon-to-be former colleagues to risk another four years in opposition.