Feral horse numbers in the Kosciuszko national park have surged, with new survey data estimating populations climbed by thousands after the New South Wales government paused aerial culling in 2025.

Conservation advocates say the rebound in numbers demands an urgent rethink of retention zones that allow thousands of horses to remain in the park.

The government’s annual survey of feral horse populations, released Friday, estimated there were between 6,476 and 16,411 feral horses in the national park in late 2025.

This is a sharp increase on the previous year – the first survey after aerial shooting of horses resumed – when numbers dropped to an estimated 2,131-5,639 horses.

The culling of horses and other feral species will resume in the park in June.

The NSW environment minister, Penny Sharpe, said the data confirmed the need for “continued management” to meet the legally mandated target of reducing feral horse numbers to 3,000 by mid-2027.

She said while there were early signs of ground cover and vegetation recovery in areas where horses had been reduced, overall numbers remained high and the damage caused by the feral animals to Kosciuszko’s fragile alpine environment was evident.

She said the government was looking at all options to control the numbers, including engaging an independent expert to design a reproductive control trial for horses in the park.

“No one wants to have to kill horses. But there are still too many in Kosciuszko national park,” Sharpe said.

“We will use the best available science and take a cautious, evidence-based approach to reach the required population target, in order to protect native vegetation, animals, waterways and cultural values.”

The chief executive of the Invasive Species Council, Jack Gough, said the rebound in horse numbers reflected the fact the state government undertook no control work in 2025 and showed culls should occur annually.

He also called for urgent amendments to the state’s feral horse management plan for Kosciuszko national park. The plan requires at least 3,000 horses to be retained in four zones that cover 32% of the park.

The zones were introduced by the previous Coalition government as a concession to brumby advocates that the National party demanded. Gough said the zones should be scrapped and horse numbers reduced to as close to zero as possible.

He said the parliament gave the minister the power to change the plan when it repealed the Kosciuszko wild horse heritage Act last year.

“It’s disappointing given the broad cross party consensus the government still hasn’t scrapped these retention zones and the ridiculous 3,000 horse target,” Gough said.

“This is a national park not a horse paddock.”