Former National leader Don Brash has paid tribute to outgoing MP Nick Smith, hailing him as "a very committed New Zealander".
Dr Smith announced his retirement on Monday after reportedly being told an investigation into a "verbal altercation" was going to be made public on Tuesday. He was allegedly recorded losing his temper and swearing at a "young male staffer" in July last year.
He said he regrets the incident and has apologised.
Brash highlighted Smith had been in Parliament for more than 30 years and was an "extraordinarily hardworking" MP.
"Like him or not, he's a very committed New Zealander. Few New Zealanders - few MPs - are as committed to their country as Nick is," Brash told Magic Talk's Sunday Cafe.
"He's much more a New Zealander than he is a National MP, in my view. Nick and I often disagree on subjects but despite that fact, when I was in Parliament and leader particularly… he was loyal to me, worked incredibly hard and I think he'll be missed."
Brash said Dr Smith was his deputy leader for a short time at one point but admitted: "It didn't quite work out."
"Nick was under enormous stress and strain, and took a couple of weeks annual leave and I eventually appointed Gerry Brownlee as my deputy."
Former NZ First MP Jenny Marcroft, appearing on Magic Talk with Brash, said Smith's departure isn't exactly unexpected.
"The political pundits were saying right from the start of this political term they expected Gerry Brownlee or Nick Smith to be the first to go and it just happens to be Nick Smith."
Earlier this week, National leader Judith Collins said Dr Smith had been hard-working and loyal to his electorate.
"Nick has been there for 30 years. In that time, I am not aware of any personal grievance that has ever been brought against him.
"He is very, very passionate about his work. He has been immensely loyal to Nelson."
However, Newshub has spoken to several former National Party staffers who'd either been directly affected by Dr Smith's behaviour or witnessed it. None would speak on the record.