Save the Children findings put New Zealand 17th in healthcare for mothers and babies.
An international ranking of New Zealand's risk of maternal death as 36 per cent higher than Australia's has been questioned by a government-appointed mortality review group.
But an American women's health expert says New Zealand's ranking shows the country's health care system needs to do better for mothers and babies.
Save the Children's 2015 Mother's Index Rankings places New Zealand 17th of 179 countries.
The rankings are based on five health and social measures.
New Zealand's rankings on each of these are: 23 for risk of death during pregnancy or childbirth; 25 for the death rate of children under 5; 1 for expected duration of education; 19 for national income per capita; and 17 for proportion of national MPs who are women.
The report states New Zealand's lifetime risk of maternal death is 1 in 6600, similar to the UK's of 1 in 6900 but significantly worse than Australia's risk of 1 in 9000.
Alison Eddy, deputy chairwoman of the Perinatal and Maternal Mortality Review Committee, doubted New Zealand's ranking on maternal death risk and especially the disparity with Australia, which she said had a weak maternal death reporting system when compared with New Zealand's robust processes.
New Zealand recorded 15 or fewer maternal deaths a year from 2006 to 2012, the latest reported year, of which suicides and other causes not directly related to pregnancy or birth were the majority.
Ms Eddy, a midwife, said when it comes to reporting of maternal mortality and registering births New Zealand's similarity to the UK in the ranking was probably reliable because it had a strong maternal mortality review system.
She also said New Zealand's death rate of babies from mid-pregnancy to soon after delivery - perinatal mortality - was very similar to those of other developed countries.
"In our annual report last year we compared to the UK and Australia and we are not statistically different."
An OECD report in 2013, in which Iceland had the lowest infant mortality (under age 1), put New Zealand in 30th place out of 40 countries, although the report notes that reliable comparisons are frustrated by varying definitions.
But US women's health expert Professor Stacie Geller, who is doing maternity research at Otago University in Wellington, said the Save the Children report indicated New Zealand needed to do better in maternity care.
"The best countries to have a baby are Norway, Finland and Iceland but their health care models are not fundamentally different than yours. You should be in the top 10," she said.
She said the report noted the higher infant mortality rates of Maori and Pacific children, which others have attributed in part to higher rates of SUDI (sudden unexpected death of an infant).
Women's health care advocate Lynda Williams agreed with Ms Eddy that New Zealand was probably misrepresented in the maternal death rankings - "I think we are way above what is listed in the report.
"... I think we have a maternity care system which is one of the best in the world."
She said New Zealand's ranking at 25 for child deaths was more likely to be reliable, because of child abuse, poverty and Third World diseases.
Good care made the difference
Amelia Ene's delivery of her baby Neriyah, now 6 months old, did not go as she had planned.
"I had her in Middlemore Hospital and it was a caesarean section. It was unplanned, an emergency c-section after 26 hours [of labour].
"Then I had to wait. There was an emergency that had priority over me."
Mrs Ene said her operation went well, but was preceded by dreadful labour pain while anaesthesia was organised.
"It took them a while to find the right place to stick the needle in my spine."
But she considered her maternity care good quality - "and it's free".
"I was in hospital for one night, then they transferred me to a birthing unit [in Botany Downs]. I stayed there for three nights.
"They do courses while you're in there. There's midwives there that educate you about everything and what to expect and to prepare yourself for. I never expected that from a birthing unit."
From the report
Best and worst places for mothers and infants:
17 New Zealand
24 United Kingdom
33 United States