Defending its protest action at the Port of Tauranga, Greenpeace says New Zealand is shooting itself in the "economic foot" by importing palm kernel extract (PKE).
Greenpeace says palm plantations are a major factor in the destruction of rainforests in South-east Asia, and New Zealand - which trades on its reputation of being clean and green - is sealing its own economic fate by accepting commodities produced in that way.
On Wednesday, a group of protesters chained themselves to the cargo vessel East Ambition off the coast of Tauranga in an attempt to stop an incoming shipment of PKE. Fifteen of the group were arrested and will face charges.
Federated Farmers president Don Nicholson says they committed "economic treason" and showed the rest of the world that New Zealand is potentially an awkward country to trade with.
Tougher penalties needed - port chiefs
Mr Nicholson believes the protesters should be charged with piracy. So does the chief executive of the Port of Tauranga, Mark Cairns, who says Greenpeace has a right to peaceful protest but in this case its protesters put themselves, the ship's crew and the police at risk.
Greenpeace says it did not put anyone at risk, but Mr Cairns disagrees. He and the chief executives of three other ports - Nelson, Lyttelton and Timaru - believe tougher penalties should be considered as a deterrent to such activity in New Zealand.
If protesters tried it on a ship in northern European waters, Mr Cairns says, they would be regarded as pirates before they even got on board, and shot.
Small fine likely, if convicted
The 14 people taken off the East Ambition on Wednesday night and a person on a support boat have been charged with the minor offence of unlawfully boarding a ship, and will most likely get a small fine - up to $2000 each - if convicted.
New Zealand criminal law has a piracy provision, but only in cases of a suspected violent act or robbery on a ship.
Tauranga police area commander, Inspector Mike Clements, told Morning Report that inquiries are continuing and further charges cannot be ruled out. Stopping the protest was a costly exercise, he said, and the police may seek some form of reparation.
Rainforests not affected - Fonterra subsidiary
Greenpeace says the PKE trade is contributing to the clearance of rainforest for oil palm plantations in Malaysia and Indonesia, devastating the natural habitats of animals like the orang-utan and the Sumatran tiger.
It says most of the feed on the East Ambition is destined for Fonterra dairy farms and Fonterra is increasing demand for the product through intensive farming.
But Fonterra's rural merchandising company, RD1, says considerable effort has been made to ensure the feed brought to New Zealand does not reduce rainforests. Chief executive John Lea says he has personally visited the company's supplier to see its operation.
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