Humane Society International Australia offered the reward on Wednesday as an incentive for anyone with information leading to the arrest and conviction of those responsible for mutilating and killing three platypuses found in Albury Botanic Gardens in recent weeks.

Anyone with information can contact Crime Stoppers at Albury Police on (02) 6023 9299.

HSI senior program manager Evan Quartermain said platypuses were protected under the NSW National Parks and Wildlife Act 1974. 

“This beloved wildlife species is very rare and has the highest level of evolutionary distinctiveness of any mammal species worldwide,” he said.

"It is heartbreaking that such senseless acts have taken place towards such beautiful and innocent creatures and impossible to comprehend why anyone would be so cruel.

“HSI hopes that by offering this substantial reward, we will help to bring the perpetrators to justice before more platypuses or any other wildlife is targeted.”

HSI Head of Campaigns Nicola Beynon said it was vital the offenders were caught.

"It is essential that the culprits responsible for killing the platypuses in Albury are held to account, particularly in light of the fact that overwhelming evidence suggests that people who commit acts of violence upon animals present a high risk of going on to commit violence against humans,” she said.

Harming native animals is an offence in NSW and penalties include a fine of up to $11,000 and/or six months’ jail.