While the government recognised some cultural heritage value to the wild horses, Mr Speakman told the ABC: "The numbers need to come down quite dramatically, because they're unsustainable and they're doing serious damage."
Opponents of the plan say brumby numbers do need to be controlled, but the methods suggested to carry out the cull make it a massacre.
"It's not just the scale of it, it's the methodology," said president of the Snowy Mountains Bush Users Group (SMBUG), Peter Cochran.
"Shooting is a cruel and unnecessary disgrace."
The plan proposes ground shooting, trapping, aerial mustering and fertility control as methods of culling, and rehoming brumbies that aren't killed.
It rules out aerial shooting - banned in NSW following a botched slaughter of 600 horses in the Guy Fawkes National Park in 2000.
It also rules out a return to traditional methods of control including brumby running, trapping and roping from horseback - something the SMBUG labels "a disgrace".
"This was the way this issue was managed for 150 years," Mr Cochran said.
Losing the battle
National Parks and Wildlife (NPWS) rangers are currently restricted to passive trapping methods and relocating brumbies out of the park.
That program removed 2000 brumbies between 2009 and 2014, but Tom Bagnat who oversees the plan for the NPWS told ABC News rangers needed more options.
"We're losing ... it's not sustainable for us to sit back and not try and manage the horse population to protect the natural values of Kosciuszko," he said.
Mr Cochran, former MP for Monaro, lifetime resident of the area, and the operator of Cochran Horse Treks said control of brumby numbers should be handed back to the locals, and the NPWS had nobody to blame but themselves for the population explosion.
"That's a mess of their own making - created all on their own when successive
governments threw horse riders out of the park," he said.
"Denying local horse riders access to capture brumbies in the traditional way saw the numbers increase.
"Using traditional methods of trapping and roping and haltering, educating and putting the horses to productive use is humane. There are plenty of people willing and able to do that - but they've locked them out."
There is a positive in the draft plan.
For the first time, it acknowledges brumbies have a place in the national park and recognises they are a part of our cultural heritage, Mr Cochran said.
Snowy Mountains Horse Riding Association (SMHRA) spokeswoman Leisa Caldwell welcomes that recognition of the brumby's place in the high country's heritage and folklore, but fears it will mean little if numbers are cut to 600 - a number both Snowy Mountains groups say makes the population unsustainable.
Anything less than 2000 horses will make the genetic pool will be too small and be a death sentence in itself, they say.
SMHRA says bullets are not the solution. Allowing riders back in to catch and rope is.
"That was happening until the mid-2000s. It still happens in Victoria with the permission of the parks down there. Those independent reference groups who argue it's cruel have not seen it "What's cruel, terrifying and unnecessary is ground shooting," Ms Caldwell said.
She said concerns brumbies were in true alpine areas, above the tree line, don't take into account the horses being displaced from other areas of the park now so overgrown the animals can no longer live there.
She added the plan did not address the good horses can do - pointing to overseas initiatives, especially in Europe, which have seen horses released into areas to restore national parks.
Supporters of brumby culling say the horses damage sensitive waterways and bogs which are home to critically endanger native species - and the damage from brumbies because of their size and weight is worsening - compacting wetlands, eroding stream banks and spreading weeds.
Other feral pests 'ignored'
Opponents ask why just brumbies are being targeted.
They say the park is over-run with other feral pests - including wild pigs, wild dogs, foxes, wild cats, deer and rabbits - damaging the park and not enough steps have been taken to manage them.
"They are all there in large numbers - the pigs in their thousands," Mr Cochran said.
"They are a massive problem, and for some reason their focus are horses.
"I can show you hundreds of acres which have been ripped up by pigs - they plough the ground right up.
"National Parks opposes shooting those animals. I can't see how on earth they can legitimately claim they can shoot brumbies but not wild pigs."
A 2014 survey of feral horses in the Australian Alps also noted sightings of other animals, including feral pigs, cattle, feral goats and deer.
"There were only sufficient sightings of deer ... to estimate the size of the deer population, which was estimated to be 2660. No other species were recorded often enough to calculate a population estimate," a NPWS spokesman said.
"In the past five years the NPWS pest control program has seen 1844 pigs, 934 deer, 846 goats, 2037 foxes and 1377 wild dogs being removed from reserves across the region.
"NPWS has laid 43,736 baits for wild dogs, 6734 baits for foxes, 667kg of bait for pigs and 3852kg of bait for rabbits."
Brumby advocates are encouraging supporters to submit responses to the draft plan by July 8, when the exhibition period closes.
They will limit a more concerted public campaign until after the Federal election, believing the release of the plan on the eve of the Federal Budget an alongside the election campaign, is no coincidence.
""There's no point in mounting a concerted campaign while the Federal election is on - it gets lost in all the other issues," Mr Cochran said.
"But the State Government will know they're alive after that."
