A planned cull of thousands of tahr should be stopped until "proper engagement and consultation" with hunters has taken place, says the National Party.
But Forest & Bird says skyrocketing tahr numbers clearly show hunting organisations are not able to adequately control the goat species' population.
The Department of Conservation said new monitoring data gathered over 18 months had highlighted the tahr population was much higher than expected and the Minister of Conservation, Eugenie Sage had asked for it to be reduced urgently.
The Himalayan Tahr Control Plan sets the total tahr population in the central South Island mountains at 10,000 animals (between the Rakaia and Haast Pass) and requires tahr populations to be actively managed to ensure they do not expand their range, particularly to the north and south.
Following a recent meeting of the Tahr Liaison Group, the Department of Conservation proposed reducing the tahr population by around 17,000 animals as a start to bringing the population down to the 10,000 goal. DOC would also focus on eradicating the tahr populations that had been expanding into the northern and southern exclusion zones.
Forest & Bird it strongly supported the reduction in Himalayan tahr numbers to protect New Zealand's sensitive native alpine ecosystems.
"In the last couple of decades recreational, safari, and commercial hunters have lobbied for the management of tahr numbers to be left mainly to their own efforts," said Forest & Bird's Regional Manager for Canterbury, Nicky Snoyink.
"Leaving the main management of tahr numbers in the hands of the hunting community has led to the out-of-control population increases. Instead of a population of 10,000 animals we now have a population of over 35,000 tahr on public conservation land and probably closer to 50,000 when non-conservation land is taken into account - five times the maximum population required by the Tahr Control Plan," she said.
National Party conservation spokeswoman Sarah Dowie said Conservation Minister Eugenie Sage needed to halt the cull.
"Ms Sage's decision to cull 17,500 Tahr without a consultation process with the industry illustrates her Greens-know-best approach to all matters of Government.
"She must stop this cull until her department has had a chance to consult with the hunting industry and recreational hunters properly.
"The new Minister is positioning the direction of DOC away from recreation and visitor assets."
Forest & Bird said it was very disappointed to learn that hunting organisations were opposing the proposals.
"Current levels of tahr control are not sufficient to maintain the status of tussock grasslands and iconic species such as the showy giant mountain buttercup, (Ranunculus lyalli), known as the Mt Cook lily, and rare plants such as the yellow mountain buttercup (Ranunculus godleyanus), let alone enable their recovery."
"While recreational hunting has a role in pest control, it is essential that we do not hand over conservation management to the hunters. Time after time we have learnt that recreational hunting is not up to the task of achieving the desired conservation goals."
"Because of the past failures of recreational and commercial hunting we now need to reduce tahr numbers by 80 per cent. If the hunting organisations were genuine in their claims that they want to look after the environment they would support DOC's proposals rather than opposing them,' says Snoyink.
But the NZ Deerstalkers' Association said the proposal was rushed, based on slender evidence, "and could spell the demise of a unique and valuable trophy herd".
Spokesman Bill O'Leary said more time needed to be spent setting terms and conditions for the cull, "rather than just rushing in and killing everything on sight without considering the consequences".
"We acknowledge that tahr numbers are above the level set in the 1993 Tahr Plan, and some carefully planned, highly selective culling needs to be done – but better data and more detailed planning are needed rather than killing so many tahr with undue haste."
A herd of 10,000 tahr left after unselective culling would not be able to provide a sustainable harvest of trophies, he said.
The Tahr Liaison Control Group is made up of organisations with hunting interests and conservation groups. Members include, NZ Deer Stalkers Association, Game Animal Council, Safari Club International, Professional Hunting Guides Association, Forest & Bird, Ngāi Tahu, LINZ, Wild Animal Recovery Operators, Federated Mountain Clubs, Aerial Assisted Trophy Hunting and tahr farmers.