Scientists are arguing for the archaeological excavation of a shipwreck lying buried in sand in the Kaipara Harbour after a discovery that could rewrite the history of New Zealand's early European settlement.
Carbon dating of the vessel, completed last week, puts its construction as after Abel Tasman but before James Cook.
The accepted history is Dutch explorer Tasman was the first European to reach New Zealand in 1642 and there was no-one else until Captain Cook's voyage in 1769.
A paper, accepted by the international Journal of Archaeological Science last week, dates the ship buried at Midge Bay, on the north head of the Kaipara Harbour, as being built in 1705, plus or minus nine years.
The mystery ship, which is 25m to 27m long and 6.5m to 7.5m wide, was discovered in five metres of water in 1982 by mussel fisherman Leon Searle. He contacted local man Noel Hilliam, who was part of a crew who dived down in 1983 and salvaged two pieces of wood - a teak plank and a smaller piece identified as the tropical hardwood Lagerstroemia.
The wood was kept by Hilliam and the Dargaville Museum and has recently been radiocarbon-dated and scrutinised by tree-ring experts.
The date of 1705 was calculated after taking into account the age of the timber and the length of time needed to mill and season the wood, which is native to South-east Asia.
Given known issues with deterioration of tropical timbers, the authors suggested a boat with such timber would not last longer than 50 years. The original discoverers noted the wreck had copper sheeting on its hull - a feature of Dutch shipyards by the 1670s.
Study author Dr Jonathan Palmer, a tree-ring expert, said when he got the results of the dating back, he thought: "Good God, this could be really important. It really needs excavation. It needs to be an eminent archaeologist."
Midge Bay has filled in with sand since 1982 and the wreck now lies buried under 11m of sand, though it is no longer under water. A magnetometer survey has pinpointed its exact location.
The paper cited Cook's journals, in which he documented accounts by local Maori of "earlier encounters with Europeans, with the ships having been wrecked and the survivors killed and eaten". Hilliam believes the ship is older than the dates suggested by the journal paper and that it is a Portuguese ship, and all but one of the crew were killed and eaten.
He said he supported an excavation, but it would be a "major operation".