One of the Nelson City Council's youngest elected members said councils will have to factor in changing demographics to support investment decisions made today.
The council has launched a strategy aimed at how to create a better city for older residents, in line with an ageing population.
While people were now living longer, the actual number of elderly people was set to decline as the large population bubble of Baby Boomers (those born after the end of World War 2 and the mid 1960s) aged and died.
The strategy named Nelson: A City For All Ages was a document aimed at guiding decisions over the next few decades. Mayor Rachel Reese said Nelson, like the rest of the country was ageing. She said in Nelson City, with a population of 52,000 there were now more people aged over 65 than children aged under 15.
Councillor Mike Rutledge, who was age 35, said smarter investment decisions would be needed.
"That concept of inter-generational equity is really important and every generation needs to do their bit to make sure they don't put a bow wave (of debt) down the road for somebody else."
Ms Reese said if Nelson was going to be a truly age-friendly city it needed policy, services, settings and structure that enabled people to age actively.
"We need to find the gaps and understand the needs, and the opportunities," she said.
The chair of the strategy steering group said increased life expectancy was another part of the demographic that needed to be factored into future planning.
Paul Steere said this "longevity dividend" was "the most significant social transformation" Nelson would experience.
"Ageing will impact every aspect of daily life from transport to the economy, health, housing and social connections.
"If we don't prepare now, many will struggle to adapt, and for many, ageing may not be a gift but a burden."
Ms Reese said the council felt the strategy needed to be driven by the community.
"The strategy provides a tremendous opportunity. We can harness the wisdom and experience of our older residents in a way that benefits the whole community."
The Steering Group would be working with agencies, groups and organisations to develop ideas. Consultation with the wider community was planned for 2020.