Wellington is likely to have the highest proportion of working age people of any of New Zealand's main cities by 2031, a new report suggests.

The report is the latest from the Core Cities Project, an initiative from Local Government NZ and the Business, Innovation and Employment Ministry.

The project looks at the competitive advantages and economic strengths of the country's six largest cities - Auckland, Hamilton, Tauranga, Wellington, Dunedin and Christchurch.

The report suggests that cities will increasingly use job and study opportunities to compete for younger workers as the population ages.

Co-project manager Melissa Hall said New Zealand cities were quite distinctive in terms of their economic strengths and specialisations.

"So in terms of trying to attract and be attractive locations for workers and businesses, it means they can highlight exactly what they need."

Wellington's tertiary institutions and job opportunities would give it an edge. An estimated 70 per cent of its population was expected to be of working age (14 to 49 years) in 20 years.

"The real attractiveness for Wellington is around the employment opportunities," Hall said.

Auckland, Hamilton and Wellington's working age population would continue to climb.

- © Fairfax NZ News