Two Eastern Grey Kangaroos had been beaten and had their tails removed in what was described as a "brutal" attack.

Sydney Metropolitan Wilidlife macropod coordinator Jamie Ilo said the animals were still alive when the wildlife carer found them.

"We received a call about two kangaroos on the side of the road but when the carer got there she realised they had been mutilated," he said.

"This is not the first time something like this has happened in Appin.

"In September last year some roos were found with their tails and genitals removed.

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"Whoever is doing this doesn't take the tails with them, they just leave them behind so it's purely about torture."

Mr Ilo said the person injuring these animals needed to be caught.

"To me it sounds like a budding serial killer - there is no reason for someone to do this," he said.

"They had nothing to gain, Eastern Greys are very timid by nature, they just do their own thing.

"Whoever is doing this needs to be caught."

Mr Ilo said the roos that had been attacked were on the smaller end of the scale.

"You wouldn't want to take on a fully grown male kangaroo - they can weigh up to 60 kilograms," he said.

"These ones would have only weighed 20 to 25 kilograms."

Mr Ilo said anyone who spots a mutilated or injured animal should call Sydney Wildlife and notify the police.

"The animal's safety is the priority so if you see anything like this call Sydney Wildlife on 9413 4300 so that we can help the animal - even if it has to be euthanised," he said.

"Call the cops right away and report it as a case of animal cruelty.

"We want to catch the person who is doing this."

The passionate wildlife carer also urged residents to take extra care on the road in the lead up to spring.

"Animals are starting to be more active so slow down and please report any animal accidents to wildlife rescuers," Mr Ilo said.

"There could be a joey in a pouch or the animal could still be alive."