We're being urged to re-think our attitudes towards ageing, as our population gets more and more top heavy.

The UN has declared this the decade of healthy ageing, but a new advocacy group says that involves solving some big problems that New Zealand hasn't even looked at yet.

In five years' time, one in five New Zealanders will be over retirement age.

But there are concerns that older people still seem to be invisible citizens.

We are currently in the middle of what's been designated as the UN Decade of Healthy Ageing, which has prompted organisations in the sector in this country to form an advocacy group and think tank.

The Aotearoa New Zealand National Forum for the Decade of Healthy Ageing aims to get society to re-think ingrained attitudes towards senior citizens, raise awareness and fund research and projects that will improve quality of life.

The Selwyn Foundation is one of the groups involved, and The Detail today speaks to its chief executive Denise Cosgrove.

The foundation's work started 70 years ago, looking at the tragic plight of older people with poor housing.

"People living in sub-standard housing without water, without amenities, with no money... in poverty.

"They numbered in the thousands then."

But Cosgrove says those problems are still happening today.

"We did some research a year or so ago and that number is 37,500 older people in Auckland and Northland alone experiencing multiple disadvantages across all those domains of wellbeing.

"It's going to get worse. In less than five years there'll be a million people over 65 in New Zealand."

Cosgrove says the UN decade is a platform for change.

"It's about actually people realising that the world is changing, that are getting more older people, and that we actually need to address this in a way that is going to enable people to age well, and to live healthier lives for longer."

The main issue the group wants to focus on is combating ageism.

Cosgrove says that's about how we think.

"Let's just stop and pause and ask why I went down that pathway, why did I make a judgement about that person, is it valid?"

Examples are stereotypes about old people not being able to use technical devices, or being poor drivers.

Another issue is pushing for policy and legislative change that would improve the lives of the over-65s, such as changing the rule that they're not eligible for student allowances.

And a third thrust is encouraging intergenerational activity - bringing younger and older people together to share knowledge skills and realise the value of each other. …

Go to this episode on rnz.co.nz for more details