The flu is killing about 500 New Zealanders each year - and men, Maori, Pacific Islanders and those living in poverty are at greatest risk of premature death from it.

That's according to new research from Otago University scientists who say the flu is likely New Zealand's single biggest infectious disease killer, accounting for about 1.8 per cent of deaths in the country.

A new study published this week has, for the first time in any country, estimated the distribution of flu deaths in relation to ethnicity and social deprivation, as well as gender and age group.

It found that, in the key 65-79 year age group, Maori were 3.6 times more likely to die of influenza than those of European or other ethnicity, while Pacific people were 2.4 times more likely to die during a typical flu season.

Those living in the most deprived 20 per cent of neighbourhoods were almost twice as likely to die of influenza compared with those living in the least deprived areas.

Men were also more vulnerable, with males aged 65-79 years almost two times more likely to die of influenza than females.

"Future work will update these estimates for the post-pandemic period, but we would expect the findings to be broadly similar," said study author Dr Trang Khieu, who carried out the work as part of her PhD.