''It is pretty exciting,'' tuatara expert Associate Prof Alison Cree, of the University of Otago, said.
Prof Cree and her research team believe three tuatara hatched in the wild at Orokonui Ecosanctuary in late summer, marking the first time in half a millennium that tuatara have hatched in the wild in the South Island.
In recent years, several tuatara have hatched in captivity in the South Island, and wild tuatara have hatched in the North Island.
Wild tuatara were almost wiped out on both islands following the arrival of humans in New Zealand centuries ago.
Her research team discovered the hatched eggs in late March.
Tuatara eggs generally had a long incubation period - ''from 11 to 16 months'', she said - but the incubation period from these eggs was particularly long, about 24 months.
''To incubate for so long, through two winters, is pretty significant,'' Prof Cree said.
''It's been a long time in the development of the project. But you have to anticipate that with such a long lived animal, that things will take a while.''
Although they had yet to see the hatchlings, Prof Cree and her team believed all three were female.
''The temperature of the nest was cool,'' she said.
''Soil temperature affects the sex of the tuatara, and low soil temperatures produce females ... so they will be females.''
Prof Cree and her team now had to sort through thousands of photographs taken by a time lapse camera trained on the eggs to try to catch a glimpse of the tuatara hatching and leaving the nest.
Hopefully, the tuatara population at the ecosanctuary would continue to grow, with both male and female animals, she said.
''We hope it's just the start of something that will be ongoing for Orokonui.''
