A retirement researcher says successive governments have ignored the future effect of an ageing population, and more research is needed to prepare for it.
Statistics New Zealand say 14 percent of the population is now aged 65 or older, up from 11 percent 20 years ago.
It's the fastest growing age bracket, increasing by an average of 2.9 percent a year between 2006 and 2013, and 3.9 percent in the June 2014 year.
The co-director of Auckland University's Retirement Policy and Research Centre, Michael Littlewood, said the figures were not surprising, and not enough was being done to prepare for an elderly population.
He said future costs need to be considered.
"The cost of New Zealand Superannuation is currently about a net 4.1 percent of GDP. That's expected to grow to 6.7 percent, on the latest estimates, by 2060.
"That's a more than 50 percent growth, so the question we should be asking ourselves now is whether we think the taxpayers in 40 years time are likely to think that is an acceptable number."
He said there was a lack of research in the area, and any that had been done was ignored by successive governments.
"It continues to be a shame that we're not really having a proper research-led discussion on these things.
"The Retirement Commission does its report once every three years - that largely is ignored. Some time or another we're going to have to stop that, and we're going to have to start talking."
Mr Littlewood said more data needed to be collected about wealth, and the transition from working full time to full-time retirement.
More older workers
Statistics New Zealand said the proportion of the older working-age population is also increasing overall.
In 1994, 26 percent were between 40 and 64 years old - this year that group makes up 33 percent of the population (1,467,100).
The chief executive of Age Concern, Robyn Scott, says with more people wanting to continue working for longer, some employers may have to consider changing their policies.
"There will, I believe, be workplaces crying out for and wishing to hang onto the skills and expertise of older people.
"Whether or not workplaces are prepared for that in terms of thinking through their employment policies, whether they want to have some flexibility around their employment ... whether workplaces are ready for this group is a different question."
The executive officer of the Retirement Village Association, John Collyns, said it could be difficult to find suitable land for retirement villages close to amenities in the future.