But the animal protection agency has renewed calls for more research into different, more humane methods of feral animal control.

Acting Climate Change and Sustainablilty Minister Andrew Fraser said the specialist squad of sharp-shooters killed the pigs in a 540,000 hectare area of Lakefield National Park, near the town of Laura on the Cape York Peninsula.

"On the first shoot well over 100 large boars - which do the most damage - were killed. But on this recent shoot only about 20 of these very large males were terminated," he said.

"However, the high reproductive rate and mobility of this species means control needs to be an annual event."

RSPCA Queensland spokesman Michael Beatty said while specially trained sharp-shooters was "probably the most humane" method of control available at the moment, he urged the government to investigate more humane methods like immunocontraception.

"But to be honest I don't know if that would work with feral pigs because the problem is so massive," he said.

Mr Fraser said shoots and targeted pest control programs were critical if Queensland's protected areas were to remain ecologically sound.

"Feral pigs can be eco-wreckers, destroying precious ecosystems and biodiversity if left unchecked," he said.

"Not only do they prey on native ground dwelling frogs and eggs from turtles and freshwater crocodiles, they can significantly disturb waterway corridors, and have the potential to carry exotic diseases.

"The wetlands also support significant diversity in fauna, particularly waterbirds and fish.

"You name it, feral pigs can virtually destroy a national park like this."

Mr Fraser said if left unchecked, the pigs would have multiplied to about 5000 in about a year and the feral pig population in the Lakefield National Park had decreased over four years of aerial shooting.

Mr Beatty said the RSPCA recognised the damaged caused by feral animals and recognised the need of humane culling.

"At least if they have got a specially trained group of sharp-shooters who are likely to kill the animals instantly, this is obviously better than having people who aren't trained correctly going out and shooting around willy nilly," he said.

"It's depressing that once again animals have to suffer because of the mismanagement of humans in recent times and in past times.

"We do accept that feral animals need to be controlled, if not eradicated, but we'd just urge people to use the most humane methods possible."