Parks Victoria has a management plan that outlines plans to cull the brumbies by shooting and by trapping and re-homing some.
Forest users have reported finding bodies of the animals under piles of branches during May.
Parks Victoria is trying to reduce the damage caused to forest vegetation by feral animals.
Barmah Brumby Protection Group vice-president Murray Willaton expressed disgust that Parks Victoria was implementing the cull while his group was asking for more horses to re-home.
He has personally seen about 25 bodies scattered through the park, many covered by leaves and branches.
In a 2019 consultation on the future of Barmah National Park, most respondents wanted to see the brumbies trapped and re-homed.
Parks Victoria has recently called tenders for qualified and experienced contractors to deliver safe, humane and effective ground shooting of feral animals, including but not limited to feral horses, deer, pigs, foxes, goats and cats, in the next financial year.
The tender is part of the Victorian Government’s Feral Horse Action Plan 2021, and all invasive animal control is guided by the Barmah Strategic Action Plan
A 2019 government report estimated there were about 500 feral horses in the 22,967 hectares of the park.
The statewide Brumby Action Group is planning a protest rally in Melbourne on Wednesday, June 8.