A year after it shocked scientists and environmental groups by passing a law to protect the introduced animals in one of NSW's biggest national parks, the government has now likely missed its winter window to remove horses for a second year in a row.

Stymieing the relocation efforts has been a delay in agreement within the government on the membership of a new independent community panel supposed to advise on horse management.

Matt Kean, the Energy and Environment Minister, signed off on who he wanted more than a month ago, only to have John Barilaro, the Nationals leader and Deputy Premier hold off submitting his list, government sources told the Sun-Herald.

Horse relocations reached as many as 600 at their peak in previous years. While animals can be removed from the park throughout the year, the June-July period has been preferred because any later, mares will often be in foal.

Safety risks also rise for horses and the public alike as visitor numbers increase with warmer days.

Office of Environment and Heritage staff are currently analysing data collected as part of a five-yearly survey of herds in the park. The Sun-Herald understands figures show horse numbers are much higher than five years ago.

An OEH 2016 draft plan recommended cutting the Park's then 6000-8000 horses to 600 over 20 years because of the damage the hard-hoofed animals inflict on alpine wetlands and streams.

Graeme Worboys, an honorary associate professor at the Australian National University, said it "was just crazy" bickering within the government could be stalling animal removal.

"We shouldn't be playing games," Professor Worboys said, noting that Park rules from 2008 give authorities the right to re-house horses regardless of whether a community panel is in place.

"These horses are impacting Australian native species and impacting the catchment at a time when this water is going to be needed" as drought worsens, he said.

Mr Kean, who was contacted for comment, made a point of beginning his "statewide listening tour" with a trip to the Kosciusko National Park in May.

His reference in a Facebook post to his surveying areas "inhabited by feral horses" - rather dubbing them "wild" or "heritage horses" - is understood to have irked his Nationals colleagues.

A spokeswoman for John Barilaro, though, denied the deputy premier had delayed the panel's formation.

"The NSW government is working as quickly as possible to finalise the independent community panel," she said.

"The objective is to identify the heritage value of sustainable wild horse populations within identified parts of the park - to manage brumby populations to a sustainable level."

Kate Washington, Labor's environment spokeswoman, said sensitive swamps and bogs were "being turned into paddocks".

"The headwaters of the Murray and Murrumbidgee Rivers - the lifeblood of the Murray Darling Basin - are being degraded," she said, adding Mr Barilaro "should get out of the way and let government do its job to protect this unique national park".

Independent MLC Justin Field, who visited the park last month, said the government had failed to implement its own heritage committee and plan, leaving horse numbers to "grow out of control".

"Even with the Heritage Act in place the Environment Minister has the power and responsibility to protect the environmental values of the park but internal Coalition politics is undermining this critical work," Mr Field said.