Graphic video of Sydney poultry workers cruelly mistreating turkeys at a processing plant at major retail supplier Inghams Enterprises has been turned over to Australian police.

Watch the abuse video here: Warning - graphic footage

Sydney vet Dr Mark Simpson said the behaviour shown in the footage, taken from a camera hidden in the south-west Sydney plant by Animal Liberation over two weeks, was among the worst he had seen.

He said CCTV monitoring of the slaughtering of animals should be mandatory to prevent further pain and suffering of animals.

The video, shown on Australian current affairs show Lateline last night, shows workers at the plant kicking birds, stomping on their heads and slamming them against production line machinery.

Emma Hurst, from Animal Liberation, said the workers showed complete disregard for the suffering they were inflicting on the turkeys.

"It is as though these animals are mere objects and that they are there for their enjoyment to torture them,"  Hurst told the ABC.

She said acts of animal cruelty by the workers were filmed on the secret camera every day and it appeared they went out of their way to intentionally harm the birds.

The ABC showed the footage to Ingham chief executive Kevin McBain, who issued a statement saying Australia's biggest poultry producer does not tolerate mistreatment of its livestock.

He said the company condemned the animal abuse seen in the footage and would "review, retrain and reinforce our animal welfare standards throughout the organisation".

He said the company was carrying out its own investigation to resolve "these intolerable incidents".

The ABC said Animal Liberation had given the footage to police and welfare authorities.

- AAP