Killara woman Kathy Margaret Emmins became deeply concerned as she witnessed Katrina Payne being verbally abused by her partner, Jackson Slade, on the journey, which left her in tears.

Defence lawyer Mark Cronin said Emmins' decision to say something was an example of the national television campaign urging people to "unmute" themselves when they witnessed domestic violence.

IN OTHER NEWS:

But in the end, Emmins, now 31, and her partner, Ryan McPherson, 33, and North Albury couple Slade and Payne, both 29, fought on getting off the bus.

Emmins bled profusely after she was punched to the face by Slade during the melee in central Albury on the evening of March 13.

At various points, Payne punched Slade, Emmins thumped Slade to the head with a bottle and arresting police were grabbed, pushed and assaulted.

Albury Local Court magistrate Richard Funston was aghast on Monday, describing their behaviour as "hideous", and ordered a sentence assessment report for Slade's "very serious, ugly offending".

Slade pleaded guilty to assault occasioning actual bodily harm, common assault and intimidation.

Prosecutor Sergeant Andrew Pike said while police agreed Emmins and McPherson initially acted out of concern, "Mr Slade's in a completely different category to the three other people".

The threshold for jail for Slade, who instigated the violence, had been crossed, he said.

Emmins, McPherson and Payne each escaped conviction and were placed on conditional release orders: Payne's, due to prior offending, for 12 months and Emmins and McPherson for six.

Slade will be sentenced on July 4.

Emmins pleaded guilty to common assault and assault police, McPherson to resist police and common assault, while Payne did likewise for similar charges.