Two young victims have been left traumatised after they were jumped by a gang of up to 30 teenagers at a bus stop in Melbourne’s south-west.

Friends Ricky, 17, and Xavier, 14, were waiting for a bus at the Wyndam railway station when they were approached by the group.

The two boys were sitting at a bus shelter around 7.15pm yesterday when they were surrounded by a group of at youths who asked the pair for the time.

The teens say they were surrounded by a group of more than 20 youths. (9News)

When the boys took out their phones the youths then demanded they hand them over, after disabling the Apple ID and facial recognition security barrier.

“They were just saying like empty out your pockets, give us your stuff,” Ricky told 9News.

“They grabbed my shirt, ripped my shirt and hit me on the jaw.”

The boys were waiting for a bus outside Whyndam Vale. (9News)

Xavier had his bank card, phone, airpods and a $1000 necklace, which had been a birthday present from his father, stolen as the pair waited for the bus.

“I got the necklace two weeks beforehand,” Xavier said.

Two Protective Services Officers were patrolling the train station at the time but failed to intervene, telling Xavier’s father there was little more they could do than call police because they were so heavily outnumbered.

Xavier was gifted this necklace just two-weeks ago. (9News)

Xavier’s father, Anthony Ferrari told 9News he was angry PSO’s didn’t intervene.

“I don’t think it’s a good enough excuse, they are trained to deal with those situations,” he said.

“I want the possessions returned, but mostly I want the people caught.”

One of the boys father's told 9News he thought his son would be safe if he stayed around CCTV and PSO's. (9News)

After the attack, it is believed half of the youths fled on a bus towards Tarneit while another group fled down Armstrong Road.

The main offender is perceived to be African in appearance, aged between 14-16 years old, with a slim build and about 160cm tall.

He was wearing a blue and red striped top, blue denim shorts, gold-coloured shoes and a diamond stud in his left ear