The Prime Minister has given tentative backing to a Green Party policy which would charge visitors to New Zealand to help fund conservation.
Party co-leader James Shaw announced the 'taonga levy' in a speech at the Environmental Defence Society (EDS) conference in Auckland on Thursday.
It would be a $14-$18 increase on the existing border charges for international visitors. It wouldn't apply to those who live in New Zealand.
The Government introduced a border levy in 2015's Budget, which came into force in January. It moved that burden from the taxpayer to those visiting the country.
It currently hits tourist between $22 and $26, which goes toward biosecurity and Customs, but not conservation. The Greens' plan would take the new total to around $40.
Mr Shaw says the money will be split 70:30 between the recently launched national Predator-Free New Zealand scheme, and the Regional Tourism Facilities Fund.
He says it'd bring in tens of millions of dollars "to help make New Zealand's dream of being predator-free a reality".
"The Government failed to back up its glitzy predator-free promise with the money to get the job done. The taonga levy will help make it actually happen."
It would also help tourism hotspots cope with rising visitor numbers, which show no sign of slowing. Mr Shaw says annual visitor numbers are projected to reach 4.5 million in the next six years.
"More than half of our tourists visit a national park, 80 percent go on a trek for that experience of hearing a kaka screech or seeing a tui in a tree or enjoying the wide, beautiful landscapes of our country.
"We're a country with a strong clean, green brand. So paying a levy when you enter the country that cycles back into helping protect those things is a win-win for our guests and for ourselves," Mr Shaw said in his speech.
But while the extra money would go some way to helping maintain the country's environment and to fight pests, he said the policy wasn't a "silver bullet".
"We're not suggesting this levy is a silver bullet for protecting our wild spaces and our species."
He says funding for the Department of Conservation also needs to be restored to pre-National Government levels.
Tourism New Zealand says the industry is now one of the country's largest, with total expenditure in the year ended March 2015 at $29.8 billion - an increase of 10.3 percent on the previous year.
International tourism expenditure increased 17.1 percent to $11.8 billion and contributed 17.4 percent to New Zealand's total exports of goods and services.
In this year's Budget, the Government announced $12 million for a regional mid-size tourism facilities fund, which is to be used for infrastructure over the next three years.
But Mr Shaw says that's the "absolute bare minimum" they should spare to help local councils.
"Small communities on the West Coast and Coromandel shouldn't be expected to wear massive rate hikes to upgrade sewerage systems to cope with the influx of tourists."
He says New Zealanders will think the extra cost will be worth it if it helps protect the environment and wildlife.
Mr Shaw says while some may not see conservation as a priority among other pressing problems, he says it is still important.
"Yes, it is hard to make a commitment to conservation when there is growing inequality, the threat of climate change hangs over us and many people are just trying to get through the day, but this place we live in is precious."
EDS senior policy analyst Dr Marie Brown says the tax will not only help the fight to save the environment and build infrastructure, but act as a way to involve tourists in conservation.
"The key issue is that New Zealand's biodiversity is declining and current efforts to turn that around are simply not enough.
"A major discrepancy exists between the funding available for conservation and the quantum needed to turn the tide," she says.
Labour leader Andrew Little says the policy is "in principle" a good idea.
"Having a good stream of revenue that can do the range of things that in the end is about preserving New Zealand's conservation reputation and our clean, green standards is vital - that's why people come here."
Prime Minister and Tourism Minister John Key said there was "potentially some merit in applying some sort of charge, but we'd have to make sure one, it didn't deter people from coming and secondly we have to make sure the money is spent in the right place".
"You'd also have to have substantial buy-in from the tourism sector themselves."
He says the private sector is currently considering whether a tourist levy should be suggested to the Government which could be used in a number of ways.
Mr Key says he hasn't discouraged them from looking at such a levy, and the Government would consider whether to adopt it. But he says the levy is for something the Government is already funding.
"While [the Greens] make the case there's not enough money, the Government made the case for Predator-Free NZ that that was a starting position of $28 million and over time we'd put more money in."
Mr Key said any such levy would likely go toward tourist infrastructure or marketing.