15/04/2017 8:31 AM AEST | Updated 15/04/2017 9:30 AM AEST

'Sharp Object' Used In Brutal NSW Platypus Beheadings

The string of horrific killings is still unsolved.

Mick Tsikas / Reuters
A number of platypuses have been brutally killed in NSW in recent weeks.

The Humane Society International (HSI) Australia says several platypuses savagely killed in recent weeks in regional NSW were trapped and butchered using a "sharp object".

The HSI has previously announced a $5,000 bounty after the horrific slayings in the NSW-Victoria border town of Albury.

The reward would be paid for information that led to the identification, arrest and conviction of those behind the "horrific killing of the three platypuses found in Albury Botanic Gardens over recent weeks", HSI said on Saturday.

"The despicable acts of cruelty to the gentle and defenceless animals are truly shocking, with two of the platypuses having been found with their heads cut off," the group added.

"Reports confirmed that the platypuses had been trapped and killed deliberately using a sharp object."

HSI said it remained optimistic of finding those responsible for the attacks on iconic Australian animal.

The platypus is a typically shy animal and is protected under the NSW National Parks and Wildlife Act 1974.

"It's a very rare species and has the highest level of evolutionary distinctiveness of any mammal species worldwide," HSI said.