Despite attempts to save it, the kangaroo had to be put down.
The RSPCA is calling for the public’s help to catch the person responsible for the kangaroo attack.
Spokesman Tim Mayne said the crime was punishable by hefty penalties.
Any person convicted of animal cruelty could face a fine of up to $50,000 or five years’ jail, he said.
“The message is that if you inflict injuries or any form of cruelty on defenceless animals and we catch you, then we will enforce the full extent of the law and you will be punished,” he said.
The kangaroo’s death was the third major cruelty incident in as many weeks.
Veterinarians removed 23 pellets from the horse’s body – from its head through to its rib cage.
It is still undergoing treatment and there are concerns it may lose its right eye.
Police are investigating both incidents.
“The fact that RSPCA has had three reports of three separate animals shot with weapons is appalling,” RSPCA CEO David van Ooran said.
He said under the Animal Welfare Act 2002, penalties of up to a $50,000 fine and five year’ imprisonment apply.
The unlawful killing of native animals is also an offence under the Wildlife Conservation Act 1950, which carries a penalty of $4,000 for protected fauna and up to $10,000 in the case of rare or specially protected species. In addition to these provisions, separate charges can be laid by police.
Anyone witnessing animal cruelty can call the RSPCA hotline on 1300 278 3589.