Victoria has challenged NSW over its plan to extend protection to wild horses in the Kosciuszko National Park, introducing a rival strategy to control animals it says are "causing significant damage to threatened plants and other wildlife".

The Andrews government's Feral Horse Strategic Action Plan, released on Saturday, contradicts the Berejiklian Coalition government's bill, now before the NSW Parliament, to protect what it dubs "heritage horses".

"Horses are not a natural part of the Australian environment," the Victorian plan states. "Their hard hooves can cause serious damage to alpine, subalpine, montane and floodplain environments."

Brumbies in the Kiandra high country, in the Kosciuszko National Park. Credit:Karleen Minney.

The Victorian policy is in line with the ACT government and most environmental groups and scientists. They argue that the introduced species don't belong in delicate highland regions.