Disturbing video has been released of apparent extreme cruelty in a Sydney slaughterhouse.

The food authority in the state of New South Wales (NSW) on Friday closed the slaughterhouse — known as an abattoir in Australia — after viewing the footage, which it says reveals "acts of gross animal mistreatment."

The footage, screened first on the ABC Network Thursday night, showed one worker bashing pigs several times over the head with a metal bar because they had not been stunned properly in preparation for slaughter.

Last year, Australia suspended live beef exports to slaughterhouses in Indonesia after allegations of cruel and inhumane treatment of livestock.

An investigative report by ABC TV's Four Corners showed gruesome footage of cattle being mistreated and abused, leading Australia's Agriculture Minister Joe Ludwig to describe the behavior as "completely unacceptable."

"No one accepts the mistreatment of animals," he told a news conference amid a national uproar over the $684.5 million live cattle trade, 60 percent of which goes to Indonesia.

Now, inhumane practices have been uncovered in an Australian slaughterhouse.

NSW Primary Industries Minister Katrina Hodgkinson, interviewed on ABC radio on Friday, said the footage from the Hawkesbury Valley Meat Processors at Wilberforce, in Sydney's west, should act as a wake-up call for all abattoir operators.

"I've seen this footage, and it may well be a one-off, but we're certainly going to review the operations in all abattoirs as a result of this," she said. "I want to make sure that all operations right across NSW are being conducted in a manner which follows those animal welfare guidelines."

Meantime, the Sydney Morning Herald quoted from a statement by the slaughterhouse's management:

"Casual staff involved in the incident have been stood down and permanent staff have been moved to other duties until the investigation has been finalized.

"Hawkesbury Valley Meat Processors is currently moving stock from its abattoir following the suspension of operations."

Warning: the following video contains graphic footage: