Animal welfare group PETA have produced video footage of shearers abusing sheep who may be on drugs.
"They use sports enhancing drugs to shear more" one Victorian worker said.
The videos - which show sheep being stomped on, hit in the head with a handpiece and stitching up wounds without anaesthetic - were taken as part of an investigation by the US affiliate of PETA and published online.
Sam Beechy from the Australian Workers Union said he'd heard reports of sheep having eyes gouged and jaws broken by frustrated shearers.
"A lot of these unfortunate instances could well be stopped very early if farmers and shearing contractors would take action as soon as this behaviour is noticed" he said. "They're scared, they're scared to take action against the shearers."
The video footage was allegedly taken at 19 different shearing sheds in Victoria, NSW and South Australia.
Shearer piecework agreements mean the faster the shearer works, the more he gets paid and it's been suggested that some contractors don't care if their shearers are on drugs because the end result is what really counts - it's all about productivity.
But if they are being paid piece rates, I don't understand how abusing sheep adds to their tally at the end of the day.
Agriculture Minister Barnaby Joyce thinks the video is a setup. "One of the questions I ask is with the close-up shot of the man hitting the sheep - which is obviously exceptionally cruel and in many instances would mean instant dismissal - where exactly was the camera?"
"Did the person know he was being filmed, were they actually part of the process, there are a lot of questions that need to be asked."
PETA Australia has denied any suggestion that the video was a setup or staged.
There's talk of changing the payment system but it won't work. A good shearer shearing 200 a day will not tolerate being paid the same as someone who shears 130 - he'll walk away.
"There's a growing demand for our mutton overseas, we're in a good period in the next 10 years and this could affect it" he said.
Absolutely it could affect it because cruelty to sheep won't be tolerated by anyone, - not now, not ever!