Rejecting fresh calls to cull the horses, Ms Young issued photographs including one of a small two-year-old filly trapped and held in the NSW National Parks and Wildlife Service's holding yards and subsequently named Tinkerbelle and re-homed.

"This poor girl was incredibly emaciated, although you couldn't really tell how badly under all that hair," Ms Young said. "Tinkerbelle would not have survived out in the wild, but she is now flourishing, slowly putting on weight and excelling in her handling."

Conservationists say the numbers of horses in the northern end of Kosciuszko National Park are out of control, are damaging fragile environments and should be shot from helicopters. Attempting to re-home them is not practical, and cruel, in their opinion.

Farmers in Adaminaby, and people fishing at Tantangara Dam, have seen herds of up to 30 horses lately. The NSW National Parks Association says the NSW Government is responsible for the problem, for delaying a review of its management plan.

Ms Young, an environmental scientist and vice- president of the Hunter Valley Brumby Association, says there is no scientific evidence of the horses damaging the national park, and those animals re-homed settle into their new surroundings.

"Why fix something that is not broken," Ms Young said. Her organisation took in 10 horses including two pregnant mares which had been trapped in a short, three-week period in the mountains. The mares had since delivered foals.

"They are incredibly trustworthy around children due to their calm and intelligent nature," Ms Young said.

The brumby association believes the mountain environment can be preserved.

"Preserving the Kosciuszko National Park is incredibly important to us, but there is no need for this to come at a cost to animal welfare or the cultural heritage of the region," she said.

Ms Young said the number of horses had decreased since the introduction of a management plan now under review.

"The current program is working. It needs to be tweaked to improve some of the animal welfare outcomes and to increase the re-homing rates, which continue to improve each year, but the majority of the plan is good.

"Unfortunately the National Parks Association, often confused as the National Parks and Wildlife Service, are really just a vocal minority with a proud desire to see the death of every brumby in the park," she said.

"They have been unwilling to enter into any productive discussion on how to work together to help the environment," Ms Young said.

Aerial culling would terrorise the horses. " The code of practice for aerial culling of horses advises: 'Sensitive livestock such as deer, ostrich and domestic horses are easily frightened by gunshots, helicopter noise, wind and so on and might injure themselves by running into fences and other obstacles'," Ms Young said.

National Parks Association chief executive Kevin Evans says wild horses compromise biological and heritage values, and the State Government is culpable in not implementing a strategy to address the problem.

"No one is talking about eradicating the horses. It is managing the problem to alleviate the stresses. There are not enough places for the horses to be removed and going to the pet trade and there are considerable animal welfare issues in doing such a thing," Mr Evans said.

These animals are stressed by that, even if they kick one another, and that opens a wound, those individuals go to abattoirs anyway. People are in denial about the consequences of removing animals for the perceived re-homing, it is not a wonderful ending for many of the animals in that situation," Mr Evans said.