Singleton councillor Godfrey Adamthwaite is calling on the council to write to Defence Minister Christopher Pyne and raise concerns about the lack of transparency and community consultation.

The letter would also be used to ask how many horses were killed, if any were still alive, and the government's position on aerial culling on defence land, he said.

A letter would also be written to Hunter MP Joel Fitzgibbon to request his support. 

"These questions are what everyone wants to know," he said.

"We want the transparency. There has been a lack of communication and a lot of secrecy about it.

"The Department of Defence have let us down."

Cr Adamthwaite will move the motion at the Singleton Council meeting on Monday night.

A crowd of supporters are expected to attend.

Hunter Heritage Horse Association founder Kim Waters will speak about the motion at the council meeting.

Read more: Public outrage over pony cull

She urged the community to attend the meeting and show their support. The meeting starts in the council chambers at 5.30pm.

"They were part of Singleton's heritage, they've lived on the army camp since the 1930s and they were wiped out without any regard for how the locals felt," Ms Waters said.

Defence has previously said the horses were feral pests and pointed to the drought, animal welfare concerns and environmental damage as reasons for the cull.

It also said previous attempts to rehome the horses had failed.

Defence confirmed it has "substantially completed" its control methods in a statement on December 20.

Cr Adamthwaite questioned these reasons and noted the herd had been living on the base for several decades.

"There was counter arguments for everything they said and the last two media releases didn't say much at all, in fact the second one only had 34 words in it," he said. 

"I hope most of the councillors will support me and I hope it will get up without much opposition at all."