This article is more than 2 years old

This article is more than 2 years old

Former managers from the New South Wales National Parks and Wildlife Service have described a state government proposal to give heritage protection to feral horses in the Kosciuszko national park as an attack on national parks laws and urged MPs to vote against the proposal.

As debate on the Kosciuszko wild horse heritage bill resumed in the NSW parliament on Tuesday, the International Union for Conservation of Nature wrote to the government warning that damage to the park because of the plan would hurt Australia’s reputation.

In the letter, addressed to the NSW environment minister, Gabrielle Upton, and seen by Guardian Australia, the IUCN says it is concerned the bill has “social and economic implications as well as conservation impacts”.

It states that “damage to the ecosystem and biodiversity values of the Kosciuszko national park due to the proposed management actions would be detrimental to the reputation and status of Australia and NSW’s record for nature conservation”.

NSW brumby plan makes Kosciuszko conservation 'impossible', RSPCA says Read more

It calls on the state to find a science-based outcome that respects the NSW National Parks and Wildlife Act.

Former managers from the parks and wildlife service told Guardian Australia they were concerned the bill was an attempt to change the way the Kosciuszko national park was managed.

Graeme Worboys, an associate professor at the Australian National University’s Fenner school and a former executive director of the parks and wildlife service, said the bill was “not about the welfare of horses”.

“It’s about the transfer of the management direction of the Kosciuszko national park from the National Parks and Wildlife Service to a community advisory panel,” he said. “This is a transfer of the management of Kosciuszko from ecological caretakers – the rangers – to horse managers. It’s basically destroying the environmental protection of one of Australia’s greatest national parks.”

David Darlington, a former regional manager of the NSW National Parks and Wildlife Service, including of the area covering Kosciuszko national park, said the bill “is one of the biggest attacks on the National Parks and Wildlife Act that I’ve ever seen”.

“Whenever I returned to that same area, it was just so obvious that the horse numbers and the impacts from horses had increased and that was the situation at every site,” Darlington said.

The NSW government says its bill will still allow for the removal of brumbies from the park through trapping.

“The proposed brumby legislation seeks to strike the best balance between the heritage status of brumbies and the protection of Kosciuszko national park,” a spokesman for Upton said. “It provides for the removal of brumbies from the national park, which is in line with community expectations and is also consistent with preserving the natural environment of the area.”

NSW Labor’s environment spokeswoman, Penny Sharpe, said it was “an extraordinary step” for the IUCN to write to the environment minister to ask her “to intervene to save the Kosciuszko national park from one of her colleagues”.

The bill has been moved by the deputy premier and NSW Nationals leader, John Barilaro.