Five teenagers have been charged after an assault in Melbourne’s west that left a good Samaritan in a critical condition.

Victoria Police said three boys, aged 12, 13 and 15, and two girls, both aged 14, had allegedly tried to steal items from a shop on Hampshire Road in Sunshine just after 2pm on Saturday.

A 60-year-old man, who was working nearby, came to the aid of a shop worker, who was in a scuffle in the street over the goods.

It’s alleged the man, who remained in a critical condition in the Royal Melbourne Hospital on Sunday night, was set upon by the teens.

The teens, from the Brimbank and Banyule area, who cannot be named, have been charged with affray, violent disorder, intentionally causing serious injury and intentionally causing injury.

Four teens were arrested near the incident by protective service officers and members of the transit safety division, while the 12-year-old boy was arrested at his home on Saturday night.

On Sunday afternoon, Magistrate Robyn Hamilton adjourned remands for the accused until August 7.

“Their young age is a very upsetting factor,” she said.

“It’s inevitable that in this case there will be different charges and in that case, you know that I may refuse bail in those circumstances.”

The 12-year-old boy and his mother sobbed as the magistrate denied bail for the young boy. The magistrate noted that “within hours or days the victim will die.”

“This is not children just, you know, engaging in assault and running off,” she said.

“This is a case where the victim is left in an unsurvivable situation. It really doesn’t get any more serious than that.”

The incident comes just days after Victoria’s new premier, Ben Carroll, pledged a crackdown on anyone who abuses, intimidates or assaults retail, fast-food and transport workers in their workplace.

The new laws, which were introduced in July, mean culprits could face a ban from those workplaces for 12 months. Anyone who breaches the bans could face up to two years’ prison or a fine of up to $50,000.

On Sunday morning, speaking at the opening of the Ambulatory Care Centre at the Northern Hospital before charges had been laid, Carroll said the teens should face adult time if convicted.

“This was terrible what occurred to this gentleman in a retail shop,” he said.

“That’s why there is no tolerance for this sort of behaviour, it’s awful, and lifetime consequences for them, but also the offenders. It’s going to have lifetime consequences for you, because your life will be changed when you face jail time, and you’ve got to think and make sure you do not do this sort of behaviour. It is simply unacceptable.”

Carroll said his first priority as premier was the Big Build royal commission, his second was community safety.

He said he was committed to ensuring community safety was “fundamental to everything we do”.

“We are working very hard. I met with the chief commissioner last week, and I’ve told him he’ll have every resource he needs to help us tackle violent crime,” the premier said.