A cull of more than 100 brumbies on a New South Wales army base has been described as a "disturbing, open-slather slaughter" by a local councillor, who has accused the Department of Defence of dishonesty and a lack of empathy.

The Singleton Council passed a motion demanding transparency over the cull at the Singleton Army Base in the Upper Hunter in late December last year.

The motion is seeking to raise concerns with the Minister for Defence Christopher Pyne "regarding the lack of transparency, public communication and consultation regarding the recent cull", and to find out if any brumbies remained on the base.

Councillor Godfrey Adamthwaite put forward the motion and accused the Department of Defence of being dishonest throughout the process and spoke of the department's lack of information about the cull given to the public.

He said the department seemed to lack empathy for the community's concern for the brumbies, a group of wild horses that have lived on the base for almost a century.

"They don't seem to answer to anyone but themselves, we never wanted any sensitive military information, just the truth about what was happening to the horses," Cr Adamthwaite said.

"They said no mares or foals would be culled, this just simply wasn't true.

"We just want to know why this had to happen at that very moment and no other alternative was possible."

'No other viable options'

Residents protested against the decision to cull brumbies at Singleton Army Base in December 2018. ( Supplied: Kim Waters )

In a statement, the Department of Defence said it had considered carefully a range of options to control feral horses on the Singleton Range and concluded that an aerial cull was appropriate.

It said "there were no other viable, humane measures to control feral horses in a remote area where unexploded ordnance is present".

While it had not publicised the date of the cull to minimise public risk, the department had issued three press releases in late December.

The first on December 18 set out the actions taken and the reasons behind them, and the others, on the 20th and 21st, were updates on the results of the cull.

Defence said at the time no feral horses remained on the base and has confirmed that remained the case.

Community tried to offer alternative

A Hunter-based horse advocacy group said they tried on many occasions to provide a more humane alternative to the cull but were either knocked back or ignored.

The co-president of Hunter Heritage Horses Kim Waters said her group offered to evacuate every brumby from the base.

"We said we'd capture them, re-home them — everything would be done by us and the costs bared by us."

"It was just lies, continual lies, they said they'd look at our proposal and on one of those days they just shot the horses anyway."

But in a statement released just before the cull, the department said it had tried to capture and rehome a number of feral horses in the area in 2014.

It said "the trial was unsuccessful due to the trauma and stress suffered by the horses as a result of exposure to live fire and bombing activities on the range".

Ms Waters said the Singleton community felt like they had no say about the future of the brumbies, which shared a common bloodline from Welsh Mountain ponies dating back to the late 1800s.

"They lied about why they did it, saying they were starving and had no water, were inbred and untameable … all of this was just simply untrue," she said.

"The decision was made by people in Canberra who sit behind their desks and don't get held accountable.

"They've slaughtered Singleton's brumbies. Where's next?"