The government will need to invest some "serious coin" in the Nature Heritage Fund if it wants to buy up wetlands on private property, according to West Coast Regional Council chief executive Mike Meehan.
Conservation Minister Eugenie Sage has observed that people with wetlands or significant natural areas (SNAs) on their land can offer to sell to the Crown via the fund.
But it has a budget of just $6 million a year from the conservation budget.
Despite that, it had managed to buy a number of wetlands and native forest areas in the past, from landowners including West Coast farmers, Sage said.
Meehan said $6m would be a drop in the bucket, given the quantity of land affected on the Coast by the government's initiatives to protect biodiversity and freshwater.
"It would go nowhere, when you look at the size of some of the blocks identified as wetland or SNA."
The Coast had about 5000ha of wetlands on private land, and an estimated 40 percent of private land with native forest or other ecological value could be classified as SNA, Mr Meehan said.
Ross landowner Arthur Thomson would be happy to sell to the Crown for a fair price - but says the government cannot afford it.
Some 250ha of his land, adjoining the West Coast Wilderness Trail cycle track, is classed as wetland, and the Department of Conservation (DOC) had expressed an interest in the past, Thomson said.
"DOC bought land off my neighbour with funding from Oceana Gold and they came and had a look at mine and said they'd like to buy it. But they couldn't - they didn't have the money."
DOC had suggested he put the land under a QEII covenant, but he refused.
"I'm not giving it away - those buggers came down here and objected to goldmining," Thomson said.
The government would do better to put the money it was pouring into the Pike River Mine recovery project, into purchasing land it wanted protected on the Coast, he said.
Rahu Saddle farmer Kerry Wells said he would also be willing to sell his large swamp but DOC had been unable to offer a fair price for it.
Wells bought the 480ha farm near Springs Junction in 2015 - and 220ha of the property is now classed as wetland.
"The farm had been in my wife's family for 100 years, and they never developed the swamp. I bought it for its potential, our lawyers checked the title and there was nothing to stop us developing it, but DOC said they'd be interested in buying the wet part. But they only offered $1400 a hectare."
The Conservation Minister has said compensation for landowners like Wells is not on the government's agenda, just as landowners who destroyed biodiversity habitat have not compensated the community for that loss.
But Wells said much of the wetlands that had been destroyed in the past 20 years had been destroyed by the government itself.
"Landcorp drained a hell of a lot of land for dairy farms, and now they're telling us we can't touch our own freehold property."
Meehan said the regional council had spoken to the Conservation Minister about the inadequacy of the Nature Heritage Fund, and the need to increase it.
"We have said, if New Zealand is serious about protecting these areas, the fund will need a heck of a lot more than $6m."
DOC was being forced to prioritise areas that currently had no protection at all, over areas that had some, he said.
"In Mr Thomson's case, he has a schedule two wetland so it has some protection under the regional plan; you'd need resource consent to do anything there."
Sage has said DOC is hoping to secure more money for the Nature Heritage Fund in the coming budget round.
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