The findings, just published in the journal Nature Communications, incorporate results of research by international teams involved in two major projects led, respectively, by Richard Holdaway, of Canterbury University, and Chris Jacomb, of Otago University.
The research, backed by Marsden Fund grants, concludes moa had become extinct before the mid-15th century, much earlier than the previous traditional view.
''It used to be thought that it took at least 500 years or more,'' Mr Jacomb, of the Otago anthropology and archaeology department, said.
But the latest research, partly based on new high precision radiocarbon dates of moa egg shells, including in Otago, indicates moa was extinct little more than a century after Polynesians arrived in the 14th century.
Such extinction resulted inevitably from the hunting of the slow-breeding flightless birds.
Most of New Zealand's early inhabitants would have been living in the South Island at the peak of hunting, and the moa's disappearance later contributed to big decline in the human population there.
The study also highlights the relatively small size of the country's overall human population when moa became extinct-2500 people at most.
This reality was likely to be of international scientific interest.
It had often been suggested that people could not have caused the extinction of ''megafauna'' such as the mammoths of North America or giant marsupials in Australia because the human populations at the time of the extinctions had been too small, but that argument could no longer be used.
Moa extinction was also ''a really good example'' of the issues being highlighted in concerns about environmental sustainability being highlighted this century, he said.
''It may be a little bit extreme. It's striking because the animals are big and dramatic and probably [they were] gone in a hundred years.''
The researchers calculated that the Polynesians whose activities caused moa extinction had among the lowest human population densities on record internationally.
During the peak period of moa hunting, there were fewer than 1500 Polynesian settlers in New Zealand, or about 1 person per 100 square kilometres, one of the lowest population densities recorded for any pre-industrial society.
Moa were exterminated first in the more accessible eastern lowlands of the South Island, at the end of the 14th century, just 70-80 years after the first evidence for moa consumption.
Their total extinction most probably occurred within a decade either side of 1425AD, barely a century after the earliest well-dated site, at Wairau Bar near Blenheim, was settled by people from tropical East Polynesia, the researchers said. The last known birds lived in the mountains of northwest Nelson.
• An earlier scientific study, published last month, and involving researchers from Auckland University and Landcare Research, also highlighted the rapid decline of the moa, but suggested a slightly longer period of moa survival - less than 200 years.
