NSW Nationals MP Leslie Williams has resigned from the party and joined the Liberal Party. The Port Macquarie MP said the events of recent weeks had cemented her decision.

Ms Williams said people in her electorate were "very angry" about Nationals leader John Barilaro's recent threat to the Berejiklian government to take his MPs to the cross bench over changes to the state's koala protection laws, which he described as a "nail in the coffin for farmers".

Ms Williams had opposed Deputy Premier & State Nationals leader John Barilaro's threat to move the Nationals to the crossbench over the koala policy.

The Deputy Premier was forced to back down after a crisis meeting with Premier Gladys Berejiklian and is now on 'Mental Health' leave.

In a statement on Sunday, Ms Williams described Mr Barilaro's actions as holding the Premier and the Government to ransom, adding that doing so was "unnecessary, unhelpful and frankly politically reckless and unreasonable".

"The events of the past week have represented a further example of a course of conduct and dealing that has once again effectively been condoned and failed to be addressed," she said.

"My community deserves to be represented in Parliament by members and leaders that are focused on their needs and their aspirations and they rightly expect to have policy overshadowing politics."

The political crisis was prompted by a policy that aimed to protect the habitat of koalas.

The Koala Habitat Protection State Environment Planning Policy (SEPP), means farmers and property owners must jump through more hoops if they want to clear land.

Previously, the policy identified 10 koala-feed trees based on science from 1995, and studies localised to NSW's north coast.

But the proposed policy expanded that definition and included 123 trees identified by experts who said they were used by koalas for food, shelter and social needs.

Mr Barilaro said the new guidelines went too far, stripped landholders of rights and did nothing to support koalas.

Eden-Monaro by-election spat another sticking point

The 'Koalagate' policy stoush is not the first issue on which Ms Williams has disagreed with her party leader.

In May this year, she called on Mr Barilaro to quit his position after a spat with a Liberal colleague about the Eden-Monaro by-election.

Mr Barilaro had considered contesting the Eden-Monaro federal by-election, but later announced he would not, citing family reasons.

The Deputy Premier was then quoted using vulgar language to describe Coalition colleague Andrew Constance for entering the race.

Mr Constance, a Liberal MP and NSW Minister for Transport, withdrew from the race 24 hours after announcing his intention to run.

He initially pointed to unfinished business with bushfire recovery and transport as his reasons, but later said he "hadn't signed up to, you know, contest federally to be called that type of smear".

Ms Williams said she was left feeling "frustrated" and "disappointed" by Mr Barilaro after his spat with Mr Constance, adding he had embarrassed the party and the community.

Mrs Williams resignation places the Port Macquarie electorate in a difficult position.

The National Party is sure to field a candidate in the next State election, if so, and if Mrs Williams decides to run for re-election again as a Liberal, she will be up against the well oiled Port Macqaurie National Party machine, maned by her old comrades.

If such a scenario where to eventuate, then a split in the conservative vote could be expected.

Some conservative voters would remain loyal to Leslie and go Liberal, whilst others would stay with the National Party no matter who the candidate was.

Such  a split could possibly leave the door open for either the Labor party or an independent, like Rob Oakeshott, to move in with a majority and take the seat.

Is this a watershed moment for Port Macquarie:

Personalities aside, at the next State election voters will (Effectively) be asked to decide whether they see the Hastings as a 'Rural' community, in which case they'll tend to vote National, or whether they see the area as 'Metropolitan & Urban', ln which case they'll vote 'Liberal'.

Either way, I bet they're having a party at the State Labor party HQ tonight - Let the games begin !