The amount you need in the bank for a comfortable retirement

Couples who want to keep living the high life in their retirement will need to have close to $800,000 saved up, according to a new report.

"You're gonna need to save between you - it's important to remember there are two people saving this - in round figures, about $800,000 between whatever age you are and by the time you get to retirement," author Claire Matthews told The AM Show on Thursday.

The Westpac Massey Fin-Ed Centre report, which Matthews authored, said this amount - $787,000 to be more precise - would give couples "choices" in their retirement, if they wanted to keep living in the city. In the provinces, they'd need $493,000.

For a single person in the city, they'd need not much less - $764,000. In the provinces, they'd need $411,000.

Super rates depend on your relationship status and living arrangements, but can be as high as $411 a week for a single person and $633 for a couple.

But even if you were happy to live a "no-frills" lifestyle, Matthews says you'd need $200,000 on top of your superannuation. And if you don't own your own home, forget it.

"For those that are living the no-frills [lifestyle] and particularly trying to get through on NZ Super, they really need to be in their own home, mortgage-free. If you're in rental accommodation, the rental cost actually means even straight NZ Super and 'no-frills' is probably out of reach."

KiwiSaver is key, Matthews says, but you need to put more in than just the bare minimum.

"If it's just the basic KiwiSaver, you probably are actually going to struggle still, if you do the minimum. But if you increase your contributions to one of the higher contribution rates, then you will get there. But KiwiSaver would certainly be a good stop on the way."

She says KiwiSaver could be improved by offering more contribution rates, as it can be difficult to go from 4 to 6 or 8 percent.

"If you could have smaller increments, that would be really helpful, in my view."

Earlier this year, the Westpac Massey Fin-Ed Centre said $785,000 was needed. The Commission for Financial Capability in 2016 estimated a 'choices' lifestyle would cost a couple $649,779.