National Leader Christopher Luxon is doubling down on raising the retirement age despite calls for it to remain at 65.
A report by the Retirement Commission said the superannuation age should remain at 65, warning political parties any change would further disadvantage women, Māori and Pacific peoples especially.
But Luxon continued to propose lifting the superannuation age to 67.
He said the retirement age needed to reflect an evolving society and economy.
"We've got to face facts - we've got an aging population, every decade we live another 1.3 years in terms of life expectancy and we've also got a rising level of cost, as a consequence," he told AM.
National wanted to see the retirement age lifted in a "slow and gradual" way, Luxon said.
Luxon was asked what he would say to those working in labour-intensive jobs, such as the building industry, who would be forced to work an extra two years.
"Well, then let's look at some other things, if that's necessary, in terms of support that we might need to have for people," he said.
"I worked in organisations where I had workers that had been with the company, say, for 50 years or 40 years and you can change the types of roles that you can do.
"A lot of builders that I talk to, frankly, when they're in their 30s their bodies are going through some pretty tough times and they often then change the type of role they do - they might be less on the tools and more into the project management side of things.
"I get it - it's really tough but you have to rule a line somewhere and many other countries are already at 67."
AM host Ryan Bridge pushed Luxon to clarify if National would provide support for people working in labour-intensive jobs who hadn't upskilled.
"You're saying, there might be support?" Bridge asked.
"Well, we've got, you know… whether it's disability payments or all those sorts of things but, what I'm saying is, on the superannuation thing, you have to draw a line somewhere," Luxon said. "The pragmatic, practical thing is to give people plenty of time to adjust.
Meanwhile, leading economist Brad Olsen believed leaving the retirement age eligibility as it was would be short-sighted.
Olsen, from Infometrics, told AM Early he believed the age needed to change in order to reflect New Zealand's aging population and financial hardship.
"In my mind, we've got to change with the times," he told host Oriini Kaipara. "As those times are shifting, people are living longer, they're spending now 20 percent of their life on New Zealand super and it is increasingly becoming a costly exercise.
"Let's remember, in 2021 New Zealand spent $15.5 billion on New Zealand super - that's about 18 percent of our total tax take and just slightly smaller than the entire education budget."
Olsen said New Zealand would face an increasing affordability challenge to keep the retirement age at 65.
"Let's remember, back in the 1990s - we saw about six workers supporting every retiree on New Zealand super. At the moment, we're looking at about four workers supporting every retiree and, by 2050, there'll only be about 2.5 workers supporting every retiree."
The Retirement Commission's report found 40 percent of people aged 65 and over had virtually no other income besides superannuation and another 20 percent only had super and a little extra.
Even with superannuation, nearly a third of people didn't think they'd have enough for retirement unless they continued working past 65, the report found.
With declining homeownership rates and rising living costs, more people were working for longer because they hadn't managed to save enough, still had mortgages or were paying rent, Retirement Commissioner Jane Wrightson said.
