Auckland Central National MP Nikki Kaye "will make her own announcements about her future when she is ready", Gerry Brownlee says amid speculation she is stepping down.
He wouldn't make any further comment and said he didn't "know about that decision just yet".
Several media outlets are reporting Kaye will resign later on Thursday.
Kaye was the National Party deputy leader until Tuesday when leader Todd Muller suddenly resigned, leaving the party in disarray. MPs quickly flew to Wellington where late on Tuesday it was announced Judith Collins would become leader, with Brownlee as deputy.
Collins is expected on Thursday to announce what she has previously said would be a mild caucus reshuffle. The leader said on Wednesday she expected to see Kaye in the education spokesperson portfolio.
Michael Woodhouse was dumped from the Health portfolio on Wednesday in favour of Dr Shane Reti, with Collins taking issue with him not informing the Minister of Health that he had received personal information of COVID-19 patients from former National President Michelle Boag and part of Kaye's Auckland Central campaign team.
National MP Hamish Walker revealed last week he was stepping down after admitting leaking similar information to media. He also received the information from Boag, who went on to resign her party membership.
Woodhouse didn't send the information to media, but deleted emails last week.
It has been reported that Kaye was instrumental in decisions made by the National leadership last week.
Reacting to speculation, political commentator Bryce Edwards told Newshub that Kaye's resignation wouldn't be good news for the centre-right party as it won't help create an image of unity.
"This is absolutely devastating for National. It really undermines the new leader, Judith Collins, just when she is trying to be that fresh breath of air, showing that the party is united, confident," he said on Thursday.
"It seems that the events of last week just carry on reverberating and it seems that Nikki Kaye is going because of what happened last week… deputy leaders have a role of looking after the caucus and keeping everyone in line, keeping everyone united.
"Todd Muller as leader really was just spokesperson for the party. He was the person that had to be the outward facing leader. It was Nikki Kaye's role to deal with Hamish Walker, to deal with Michael Woodhouse. Obviously, she didn't do that well. We had what was just a terrible week for National."
Following Collins and Brownlee's election as leaders, Kaye sent them her congratulations.
"They have more than 40 years political experience. Judith has a great track record as a senior minister and a highly effective opposition performer. A lot of people don’t know all of Judith’s background, she has been a fighter and a fantastic local representative."
During her time as deputy, Kaye came under criticism while trying to defend the diversity of the caucus. She referred to frontbench finance spokesperson Paul Goldsmith as Māori, which he later denied being.
Kaye entered Parliament in 2008, taking Auckland Central off Labour. She would take on - and defeat - future Prime Minister Jacinda Ardern twice.
The race for that electorate at this year's election is now up-in-the-air.
"[It's] an electorate that Nikki Kaye has held for a few terms and it now makes that electorate race open… I think [Green MP Chloe Swarbrick] now has a very strong chance. She must be the frontrunner for that electorate. That could have a significant consequence for the election," Edwards told Newshub.
The Green Party has been around the 5 percent threshold for a while. In the latest Newshub-Reid Research poll in May, the party sat at 5.5 percent. Since then it has made several announcements, including a high-profile one regarding tax.
If it doesn't hit 5 percent without winning a seat, it won't return to Parliament.
Edwards said he believes Labour will "now be under pressure to do a deal with the Greens essentially and let Chloe Swarbrick have an open run at winning this".