It's a common sight on Australia's country roads: a kangaroo carcass dragged to the verge after being hit by a car or a truck.

But it is what happens immediately after a collision, and before an animal is put out of its misery, that has wildlife carers in regional Western Australia concerned.

Sasha Boundy from Dunsborough and Busselton Wildlife Care, about 250 kilometres south of Perth, said she was worried about ignorance shown by road users.

"People just don't know what to do," she said.

"There's a massive knowledge gap down here, especially with all the cars coming down for weekends, events and weddings, they just leave them [animals] injured and suffering."

This ignorance, Mrs Boundy said, had also translated into increasing aggression and threats to "livestream" local wildlife carers when they decided that euthanising injured wildlife was the kindest option.

Animal abuse or compassion?

Mrs Boundy said two months ago she received a phone call late at night from a woman who had hit a kangaroo on a back road in Dunsborough.

Sasha Boundy says she faced driver aggression when she wanted to euthanise an injured roo. ( ABC Open contributor Tony Hanks )

After explaining to the driver that she would have to kill the animal because it was a large male with two badly broken legs, Mrs Boundy said, "She got hysterical".

"She started screaming at me that I was an abuser of animals, that I couldn't kill it because it was murder and then she pulled out her phone and told me she was going to livestream it to Facebook."

Mrs Boundy said she had no choice but to call police and wait for more than half an hour, as it was a busy night in a regional patch, and kangaroos were understandably not at the top of the police priority list.

"More and more we're having to rely on police because of idiots like this, and the worst thing about this is the length of time the animal is suffering and in horrible pain because some do-gooder thinks it's cruel to put it out of its misery."

Lack of licensed shooters

The issue is further compounded by a lack of licensed shooters, specially registered to assist in these incidents, Mrs Boundy said.

According to the Department of Biodiversity, Conservation and Attractions (DBCA), members of the public should report injured wildlife to the state's Wildcare Helpline.

Mrs Boundy said wildlife carers are at the receiving end of increasing abuse. ( ABC News: Gian De Poloni )

"The Wildcare Helpline will then engage the closest animal control agent [ACA] to assist in euthanising the animal," a spokesperson said.

But Mrs Boundy said the helpline, run by Perth-based volunteers, was not adequate.

"They don't know half of our roads, and we have one registered shooter, but he works full-time, he obviously has a life, and it's a voluntary post so it's not very often that he's been able to assist," she said.

"I would urge anyone who already has a gun licence to consider registering as a volunteer shooter because there's such a shortage and you can't just leave all these half-dead kangaroos on the side of the road."

The DBCA said there were 107 specialised volunteer shooters across the state who had been actively sought out by the government department, but it acknowledged it was a limited pool.

"The skill set and equipment required to undertake such activities are specialised and as such, this limits the number of people who can assist DBCA," a spokesperson said.

"There is a code of practice and firearms policy that volunteers are required to abide by, and safety is a priority."

Mrs Boundy said people need to know what to do themselves in regional Australia. ( ABC News: Georgia Loney )

'We are wildlife carers, not killers'

In regional Australia, where animal control agents are scarce, police have higher priorities, and wildlife carers are stretched, Mrs Boundy said people needed to know what to do themselves.

If you cannot shoot the animal because you do not have a gun licence and are not registered, then blunt force trauma to the head was the recommended method, she said.

"Who can decide? I think that's a bit of a grey area really, but should you leave the animal suffering and in pain for days on end, or should you end the suffering yourself?

"If you can't get help, then it's always best to end its suffering yourself, and anyone who knows me, knows I would never ever euthanise anything that I thought had a good chance of survival and release."