Auckland is officially one of the nicest places to live on the planet, says an international survey.

The City of Sails has been ranked the 12th best city to live in, in the Economist intelligence unit's liveability survey.

Wellington is ranked 23rd.

Issued yesterday, the survey looked at 140 cities around the world and ranked them according to stability, healthcare, culture and environment, education and infrastructure.

Auckland City Mayor John Banks' reaction to the city's placing was: "Only twelfth?"

Mr Banks said it was an exciting time for Auckland.

"One of the reasons we rate so well is because we are truly culturally diverse - the mix of people living together and working with each other - it's a unique place," Mr Banks said.

Top of the list was Vancouver because its low crime rate and the availability of good quality housing.

All Australia's biggest cities ranked highly.

Melbourne was in third place, Perth fifth, Sydney ninth and Brisbane 16th.

Wellington Mayor Kerry Prendergast said it was a fantastic result for Auckland and the capital - but Wellington especially, because of the smaller size of the city.

"We put a lot of resources into making our city a great city. We have huge support for the diverse culture andarts here, which makes it a liveable city."

Asked about Wellington's 23rd placing compared with Auckland's better rating, Ms Prendergast said the two cities could not be compared.

"For a city of 200,000 people to be ranked so high is fantastic. Auckland has more tertiary institutions, greater employment opportunities [and] they're a city of a million people."

Mr Banks said Wellington was a special place to him because he was born there, but Auckland was more special.

"I've been on the record as saying they should never have moved the capital. Auckland is the aspirational capital of New Zealand," he said. "Wellington's unique - I was born there - but Auckland is quite special and everyone knows that."

The worst place to live was Harare in Zimbabwe, followed by Port Moresby in Papua New Guinea and Colombo in Sri Lanka.

A recent Quality of Life report by Mercer ranked Auckland fourth-best city in the world.

1. Vancouver
2. Vienna
3. Melbourne
4. Toronto
5= Perth, Calgary
7. Helsinki
8. Geneva
9= Sydney, Zurich
11. Adelaide
12. Auckland
13. Osaka
17. Paris
22. Berlin
23. Wellington
39. Hong Kong
49. Dublin
51. London
52. Rome
56. New York
69. Moscow
92. Johannesburg