Nearly a third of Kiwis still working after 65 say they have to do so to pay the bills, according to new research.

It comes after an Organisation for Economic Co-operation and Development (OECD) report that found New Zealand has one of the least generous pensions relative to the working wage.

BNZ's Financial Futures study has found that 46 per cent of Kiwis plan to keep working beyond 65. And while the majority of workers over 65 were still on the job because of the value and satisfaction it gave them, 31 per cent said they needed to work for financial reasons.

Despite the report, Director of Retail and Marketing at BNZ Paul Carter told Mike Hosking most people nearing retirement don't continue to work because of financial pressure.

"The vast majority say the reason their working is because they are really enjoying their jobs, not because they have to."

Carter says it's no surprise people are working longer as many people are fitter and healthier in their 60s and 70s than previous generations.

However, he says the gap between those who choose to work in retirement and those who have to was too high and it sent a message to younger people not to be complacent.

"There's a real opportunity for people to narrow that gap by being more proactive about planning their finances."

The OECD report 2017 Pensions at a Glance out this month found retirees in the Netherlands receive more than 100 per cent of their country's average working wage but Kiwi superannuitants get just 43 per cent - ranking us 6th worst equal with Australia.

Under the Labour-led Government the age of eligibility for superannuation is set to stay at 65.

But the report warned that unless there were more people employed in older age, the ageing population would "generate lower pension levels", reducing wellbeing during retirement.

Census figures from 2013 show that more than half of men aged 65 to 69 are still working - up from 30 per cent in 2001.

Fewer women in that age group continue to work, but the proportion has increased from 15 per cent in 2001 to 35 per cent.

Of those who planned to work, only 18 per cent wanted to work full-time with 31 per cent preferring a full-time job.

The research found 72 per cent were confident they would pay off their mortgage before they retire or semi-retire despite a growing number of people taking out a mortgage at a later age.

Others planned to pay off their loan by selling up and buying a cheaper house, using savings or dividends from investments.

The bank could not provide data on what percentage of its over-65 customers still had a mortgage.

LISTEN TO PAUL CARTER TALK WITH MIKE HOSKING ABOVE