Nationals MP Ben Franklin is being backed by Premier Chris Minns to take the lucrative job of upper house president in the new parliament, which would effectively give Labor control of the Legislative Council.
The move has been widely condemned by coalition MPs, including Opposition Leader Mark Speakman and Nationals leader Paul Toole, who last week labelled it "distressing", saying it would be a betrayal of the party.
However, Mr Franklin has since contradicted Mr Toole's version of events, indicating his leader encouraged him to pursue the role.
"At one point he said if the Liberals don't want you to do it, I think you should do it anyway because this is really good for us," Mr Franklin told the Sydney Morning Herald on Monday.
He accused Mr Toole of giving in to pressure, saying he called him last week to "say that I've asked you not to do it".
The Nationals will hold a partyroom meeting on Monday, with rumours swirling of a potential challenge to the Bathurst MP's leadership.
It comes one month after Mr Toole narrowly survived a leadership challenge from Dubbo MP Dugald Saunders.
Meanwhile, the fate of Natalie Ward, touted as a future leader of the NSW Liberals, is on the line as her party colleagues also meet on Monday to consider whether to promote or stymie her progress.
The party will vote on a rule change to allow members of the upper house, including Ms Ward, to become deputy Liberal leader.
Currently, only Liberal lower house MPs can nominate and vote on the deputy leadership.
The issue has delayed Mr Speakman announcing his full shadow cabinet, ahead of parliament's return on Tuesday.
The former attorney-general was elected Liberal leader more than two weeks ago after running for the top job as a "united team" with Ms Ward and former finance minister Damien Tudehope.
Liberal insiders are not confident the party will reach the two-thirds majority needed to change the rule.
Prior to the March election, Ms Ward tried to switch to the lower house but was defeated in a preselection battle in the safe Liberal seat of Davidson.