Former National MP for Whanganui, Chester Borrows, says his party is in "damage control" following the sudden resignation of leader Todd Muller.
Todd Muller resigned on Tuesday just 53 days after winning a leadership battle against Simon Bridges.
National Party MPs are due to meet on Tuesday evening to discuss its leadership.
Both Whanganui MP Harete Hipango and Rangitikei MP Ian McKelvie have not returned calls for comment.
• Read update here: Judith Collins is new National Party leader
Borrows said he was saddened by Muller's sudden departure as the party's leader and that he was disappointed it had "all fallen over so quickly".
"I have got a lot of time for Todd, and I often pointed to him over the last little while when people asked about a possible replacement for Simon Bridges," Borrows said.
"Todd was someone who had a lot of experience and certainly wasn't new to politics."
"I guess the question now is where they go to know, and that could be quite a difficult thing."
Borrows said he wouldn't be surprised if Judith Collins took over the leadership position.
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"Judith Collins sits on the complete opposite end of the National Party spectrum from me, but I think the party needs to go someone who does have the profile and does have the currency with the public.
"At the same time she'll only drag the party to the right and take them out of the centre ground, it's in the centre where people win elections.
"If they're thinking that they're going to lose this election and are just trying to recover as much ground as they can, saving the furniture as they say, then they'll probably go with Judith."
Borrows said Collins wouldn't "grow the vote in the middle".
"All they would be doing would be lessening the defeat, which is a real shame.
"National is very much in damage control, and its very sad for those of us who have been trying to win elections for National for 20-30 years."
Borrows said that deputy leader Nikki Kaye was a "very impressive person" and had done an excellent job as Minister of Civil Defence.
"I think she's absolutely terrific, but you have to remember that absolutely terrific in portfolios doesn't mean Prime Ministerial material.
"If she came out as the one selected I'd be incredibly proud of her and i think she'd make a really good fist of it.
"She's very sensible, has a huge amount of credibility, and doesn't have skeletons in her closet."
Maintaining a sense of loyalty to the National Party was proving difficult, Borrows said.
"It would be easy to go with Judith Collins, simply because of her public profile.
"Me personally, If Nikki Kaye was selected I'd be very happy, but Judith Collins getting the nod would put me in a very difficult situation as a long time National Party voter, because I'd find it very hard to vote for her."