New debate on time of NZ settlement 

A groundbreaking study is fuelling new debate over when New Zealand was first settled. 

The research published in an American journal confirms Maori were first to arrive, but it is now likely that they may have arrived nearly 1500 years later than once thought.

A four year study on the bones of the early relatives of the rat has provided researchers with new evidence about exactly when the first people arrived on New Zealand soil.

It is believed the rats arrived here as either stowaways or cargo with the first human colonists.

"It gives us a time for when rats and people arrived in the country," says Dr Janet Wilmshurst, Landcare Research scientist.

The Landcare Research team studied centuries-old rat-gnawed tree seeds found during archaeological digs.

They dated over 100 individual seeds, pouring over rat tooth marks on them. The compelling new evidence suggests the arrival rats and Maori were between 1280 to 1300 AD, and not 200 BC, as suggested by some earlier theories.

"There's this sort of overwhelming evidence that when people with their sort of sweat of animals and plants, you know it had this instant transformation of the landscape and immediately detectable from all lines of evidence. It's overwhelming," says Dr Wilmshurst.

The study meant sending the bones to England's Oxford University where they used state of the art radiocarbon dating equipment to confirm the age. 

The Landcare team's research has recently been published in the prestigious National Academy of Sciences Journal in the United States.

Dr Wilmshurst says her findings now undermine others who have suggested Maori were not the first to colonise New Zealand.

She says because kiore or pacific rats cannot swim very far they had to have arrived with the first settlers.

"It confirms their status of being the first colonists and settlers of New Zealand," she says. 

The Landcare Research team will now use the technique to research the first human settlement on islands in east Polynesia.