The Australian Brumby Alliance was commenting as Queensland's Carnarvon Gorge National Park was closed for several days from Monday for a cull of feral animals, including horses, was undertaken.
The alliance said little information on the cull had been available from Queensland National Parks and it was unclear how, and how many animals would be targeted.
"While we do not know for sure, aerial shooting cannot be ruled out as a method of control," spokeswoman Jill Pickering said.
"Previous Government culls have shown that animal welfare protocols are not always followed in aerial shooting and the RSPCA's Code of Practice states that it is not possible to humanely kill a moving target from a moving platform such as a helicopter."
The alliance and the RSPCA in Queensland had been trying to work with the Queensland Government to ensure that management of wild horse numbers is humane.
"The cycle of 'shoot and shoot again' must be replaced with non-lethal control methods such as passive trapping handling and re-homing programs used in other states, and fertility control trials using vaccines already used in the US," Pickering said.
News of the cull was originally tipped off by Queensland property owners offering to take as many as 200 horses a year, as they reported high demand in Northern Queensland for the type of sure-footed and robust horses found in Carnarvon.
"But such programmes cost money and while members of the public are willing and able to help, they need financial assistance to get started.
"While governments argue that they do not have funds for this, they continue to find money from taxpayers to pay for aerial culls.
"The last major Carnarvon cull cost Queensland taxpayers in excess of $A200,000 for helicopters, snipers and 20,000 rounds of bullets."
Pickering said the alliance had been told by Queensland Government officials that they wanted to reduce the horse numbers in the park to a manageable level, at which point other methods might be used.
"To date, the alliance has not seen evidence that this will be the case. If the Government is serious about this, a proper steering committee to develop sound and humane management plans must be established with all key stakeholders."
In November last year, the alliance hosted a seminar in Brisbane on fertility control for wild worses. It was the first time a wide range of key players had met to discuss the potential for fertility control on brumbies.
The forum established a working party to explore how to progress fertility control for wild horses under Australian conditions so Australia could develop practical experience of vaccines, their durability, remote application methods and impact on herd behaviour, instead of relying on American scientific studies.
The seminar also provided information on passive trapping and re-homing as another non-lethal alternative.
The Australian Brumby Alliance was formed in 2008 by several wild horse rescue organisations throughout Australia to focus on the promotion, protection and humane management of brumbies.