Local councils can improve New Zealanders' health and save lives with less focus on the car and a greater emphasis on walking, cycling and public transport, researchers say.

Wellington has the highest level of sustainable travel of the main centres with 35 per cent.

A study led by Otago University (Wellington) set out to quantify what would happen if other cities had the same rate, and found there would be significant health and carbon gains.

In Auckland - which has the highest level of multiple car ownership with 55 per cent - there would be an estimated 57 fewer premature deaths each year.

As well, carbon emissions from light vehicles would be 20 per cent lower.

The figures for the four other cities in the study were (fewer premature deaths and lower carbon emissions from light vehicles):

Hamilton, 52 and 32 per cent; Tauranga, 50 and 27 per cent; Christchurch, 31 and 8 per cent; and Dunedin, 13 and 7 per cent.

The study, published in the NZ Medical Journal, says the different amounts of walking, cycling and public transport use between cities reflect different urban planning priorities over time.

Lead author Dr Caroline Shaw says the health gains are mainly through increased physical activity, but also as a result of reduced air pollution and few injury deaths.

"The costs of preferentially funding infrastructure for cars are high," Dr Shaw said.

"This research shows we can address carbon emissions while also significantly improving health in cities."