Uncovering the secrets of NZ's discovery

File photo / Nicola Topping

Two scientific papers have shed new light on how Polynesian explorers may have arrived in New Zealand, but the authors have cautioned key questions in the age-old mystery remain unanswered.

Just when and how the first people arrived in New Zealand has been a hotly debated topic for generations.

One of the contested areas is just how the Polynesians managed to traverse such vast stretches of open water -- especially by paddling canoes into prevailing easterly Pacific Ocean winds.

But now, climate researchers believe the early explorers may have found a several decades-long window of favourable winds.

Researchers from Macquarie University in Sydney and the Australian National University in Canberra said the window occurred between 1140 and 1260 -- precisely the periods when archaeological evidence indicated New Zealand was colonised by Maori.

"Our reconstructed sailing conditions during the period of East Polynesian colonisation would have enabled all of the known colonising routes, and others," wrote Ian Goodwin, a climatologist at Macquarie University, in a paper published online today in the Proceedings of the National Academy of Sciences.

The researchers said this showed an ability to sail upwind was not essential.

"Our point is that the climatic evidence suggests that an upwind capability was not necessary for exploration and colonisation of the remote East Polynesian islands (New Zealand and Easter Island) during these periods," the study said.

The wind reconstructions, based on new data about the past climate, also suggested Polynesian long-distance voyaging declined after 1300 because the winds shifted to their current patterns.

Bruce McFadgen, an archaeologist at Victoria University in Wellington, wrote that the wind patterns paper presented "a very important result and has implications not only for when settlement might have occurred, but also for return voyaging [of explorers] to tropical Polynesia".

Meanwhile, the remnants of a wooden canoe found in 2012 near the Anaweka River on the northwest coast of the South Island could reveal clues as to how the sailors made it down to New Zealand.

In a separate paper, University of Auckland archaeologist Dilys Johns said the 6m plank was likely part of a 20m canoe hull that either had two hulls connected by and supporting a deck, or had an outrigger that provided stability.

Radiocarbon dating indicated the canoe -- made with a native New Zealand matai tree -- made its last voyage around 1400.

Researchers said its carved ribs and a sea turtle carving showed strong links to Polynesian islands thousands of kilometres away.

Dr Johns said there was a possibility the New Zealand canoe builders used traditional techniques passed down through generations long after they lost contact with Polynesia.

Andrew Lorrey, a Niwa paleoclimate expert, warned there could be uncertainties in the radiocarbon dating.

But he admitted the canoe paper was "very exciting" and enriched the "prewritten history of [New Zealand] and Pacific archaeology in general".