Time's ticking for National to rebuild itself as a united front after putting Christopher Luxon's leadership to the test a second time. 

The Prime Minister survived a confidence vote launched by Chris Penk - at yesterday's three hour caucus meeting in Wellington. 

He's now dumped Penk from his ministerial portfolios and the former Defence Minister has announced he'll quit politics in November. 

Political Commentator Peter Dunne told Mike Hosking Luxon should be commended for surviving the challenge, but a third one would be a stretch too far. 

He says this has to be the end of it through to the election, and all the sentiments about the party being “100% united” have to be demonstrated if National’s to come through this unscathed.  

Dunne was sceptical of the idea that Penk had launched the challenge to put himself forward for the job, saying he felt it was "a bit far-fetched", and that Penk was more likely testing the waters for others, namely Chris Bishop and Erica Stanford. 

"I don't think he necessarily was actively working with Bishop and Stanford, although he was clearly touting their cases," Dunne told Hosking. 

"[Luxon] can't really run a credible government without those two, so they have to be there, they have to be [kept] in senior roles, and they have to be seen to be treated as senior ministers." 

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