But Age Concern says the finding may be skewed by older people's perception of what a "medium" standard of living is, and that more research needs to be done.
The report, Living Standards of Older New Zealanders, measured the lifestyles of the over-65s by looking at what they owned, how they were restricted economically and socially, and what contributed to their present financial position.
Almost 100 per cent of those surveyed received superannuation, although many also had another source of income.
About 5 per cent were found to have marked material hardship - eating cheaper meats and less fruit and vegetables to save money, postponing dentist and doctor visits, staying in bed for warmth and putting off buying new clothes.
But 39 per cent said they were unlikely to economise, were not socially restricted and had no serious financial problems.
The report said the results showed that "the current system of income support for older people has been successful in protecting the great majority of older people from hardship."
Social Services and Employment Minister Steve Maharey said the findings supported the Government's retirement policies, but reinforced the need for people to make their own provisions for retirement.
Age Concern chief executive Garth Taylor was pleased with the extent of the report and surprised by the high number of people rating their living standards "medium."
"It was certainly not our perception - nor the general perception, I would imagine."
He said it might be that the older sector were happier with less and therefore did not have the same view of a "medium" standard of living as younger people.
These were people who had lived through at least one world war as well as the Depression. They might class "making do" as an acceptable lifestyle, said Mr Taylor.
Age Concern rated a medium standard as good housing, ability to afford proper heating, being able to visit the doctor and dentist, and eating well.