A woman allegedly threatened to stab a Chinese man with a chisel after he tried to sit down next to her on a train on Boxing Day.
Footage has emerged of the encounter which appears to show the woman advancing towards the man while brandishing a chisel, yelling 'I'll stab you, dog' on a Sydney train.
A heroic onlooker wearing a white vest, who is not believed to know the man or woman involved in the altercation, then wrestled the woman onto a row of seats and disarmed her.
The argument is believed to have erupted after the woman, who was sitting on a window seat, objected when she saw the man trying to sit down two seats away from her on the aisle.
She could be heard yelling 'move, move' in front of a carriage packed full of shocked passengers and children on the Bankstown Line train at around midday on Saturday.
The man could then be seen taking a step towards her, prompting the woman to cover her face and shout: 'Hit me and I swear, go away, you touch me and I'll get these people to bring the police.
'I'm just telling you to move, look there's a seat there.'
In the mobile phone footage, the man can then be seen pushing a bench of seats over.
Wearing a bright pink hoodie and grey tracksuit bottoms, the woman then clambered over the seats and shouts: 'F****** move, you pig'.
He then stood up and she yelled: 'Don't touch me dog. Touch me brah, go on touch me you dog.'
A male onlooker than wrestled the woman down onto a row of seats and disarmed her.
She could be heard trying to justify her actions.
Annie Huang, 22, who filmed the argument on her phone, said she was 'shocked' when the woman pulled out the weapon.
'I was really scared, and it was a huge relief when the guy in the singlet grabbed her and pushed her down,' she told the Sydney Morning Herald.