It's not clear whether the animal was still alive as a man wearing green shorts punches at the marsupial's face. During the video, a second person, not visible in the footage, can be heard laughing.
It was suggested online that people involved in the attack had hit the kangaroo with their car before filming the attack.
NSW Police told 7 News they are conducting inquiries and are aware of the video.
Video shared on social media shows the man repeatedly punching the animal.
"Police are aware of videos circulating on social media regarding possible acts of animal cruelty," NSW Police said in a statement.
"Police will not tolerate violence against animals in any capacity, and urge anyone with information about this incident to contact Crime Stoppers on 1800 333 000.
"The public are reminded not to report crime via social media."
