The Right faction is expected to endorse Mr Nanva for the role of assistant general secretary at a meeting on Monday,with the view that he will then be appointed to the top job in an acting capacity while Ms Murnain's exit is finalised.
Party sources across the factions,who agreed to speak about the internal ructions on the condition of anonymity,said Ms Murnain was seeking substantial payout,with some placing the figure as high as $600,000.
But the Left faction,along with parts of the Right faction,oppose her departing with any ex-gratia payment other than her statutory entitlements.
One party operative described the situation as"a legal and political mess",and said the Left was"holding out"against pressure to support agreed terms of departure.
Several senior members of the Right,including a number of MPs,also held the view Ms Murnain should be sacked without any payout.
"It's deeply offensive to members who pay their annual fees,and to MPs who pay a $10,000 levy,that she gets to walk off into the sunset with a huge payout after irreparably damaging the party,"one MP said.
But a Right factional operative said there was a"sensible view"forming in the party's senior ranks that Ms Murnain made"an honest mistake"and she"shouldn't be cut loose with nothing at all".