New Zealand has one of the highest life expectancy rates in the world but the figures do not address health issues among poorer people, according to experts.
Women born here are expected to live for 82.81 years, and men to 78.7, according to figures released by the US Central Intelligence Agency.
The figures rank New Zealand 25th compared with 221 other countries.
The rich-lister playground of Monaco has the highest life expectancy at an average of 89.68 years.
Last on the list is the African state of Chad where the average life expectancy is 48.69 years.
Demographer Arvind Zodgekar said it was positive that New Zealand should rank in the top 25, but it could be improved if access to primary health care was made easier for people on lower incomes.
"The progress has slowed down compared to the other countries," Mr Zodgekar said. "We still have quite a good expectation of life. [But] access to primary health care has become much, much harder for middle and lower classes."
Evelyn Marsters, of the Centre for Development Studies at the University of Auckland, said the general life expectancy figure did not properly reflect how some sectors of the community were more disadvantaged.
Some ethnicity groups in New Zealand have not had their life expectancy increase in the past 30 years.
"You need to break it down and look at gender and different ethnicities, people in different jobs, to get a real idea of where life expectancy is in New Zealand, " she said.
Average life expectancy is higher in Australia (81.9), Japan (83.91) and Canada (81.48) but lower in America (78.49) and the United Kingdom (80.17).
Life expectancy at birth
* Monaco (1st) 89.68 years
* Japan (3rd) 83.91
* Australia (9th) 81.90
* Canada (12th) 81.48
* New Zealand (25th) 80.71
* United Kingdom (30th) 80.17
* United States (51st) 78.49
* Chad (225th) 48.69
Source: CIA Factbook