Mursal Biel, 18, stole a former taxi with other young people understood to have suspected links to the notorious Apex gang.

The group drove around inner-Melbourne suburbs including Richmond and Southbank over three days in April, asking people if they could use their mobile phones and attacking them or threatening to when they refused, the County Court heard at a pre-sentence hearing on Tuesday.

Armed with an extendable baton, the Springvale man asked for one man's phone and struck him to the side of the head when he refused, the court heard.

Biel and his co-offenders – who cannot be named – similarly approached two victims sitting outside their Richmond apartment to borrow a mobile phone.

"When [the victim] refused, one of the offenders produced an extendable baton and aggressively stated 'We can do this the easy way or the hard way, give me your f---ing phone'," Prosecutor Luisa Di Pietrantonio said.

He then grabbed the victim by the scruff of his jumper and pulled him closer.

One of the offenders followed the pair into their apartment and continued to demand the phone.

The victims were able to push the offender out of the door, before locking it and calling the police.

Defence counsel Caitlin Blakeney said that Biel was affected by alcohol, ice and cannabis during the crime spree.

She said that her client had started abusing alcohol when he was 16, then progressed to using cannabis and ice.

He became addicted to ice last year, 12 months after he started using the drug, and was using seven "points" of the drug at a time.

"It started as a habit, then became an addiction where he couldn't cope socially without it," she said.

"He never bought it, it was readily available within the groups [he socialised in]."

Biel pleaded guilty to theft, robbery, three counts of attempted armed robbery.

He also admitted to using stolen ATM cards to successfully withdraw $1320 cash from a victim's bank accounts, and to attempting to similarly withdraw a further $800.

The co-offenders split the money between them, the court heard.

Ms Di Pietrantonio said that when he was first arrested he had denied his involvement, and minimised it at a second police interview.

None of the victims made victim impact statements to the court, but Ms Di Pietrantonio said they would have been traumatised by the crimes.

Ms Blakeney said her client knew only one of the three other alleged co-offenders reasonably well, but would not say he was friends with the others in the car.

She said he had attempted to rehabilitate himself in custody with a number of courses, including attending Narcotics Anonymous meetings.

She said psychiatrists had assessed him as having a "borderline" low intellect, with poor impulse control.

He also found it difficult to think through the pros, cons and consequences of his actions.

Judge Felicity Hampel ordered Biel to be assessed for potential suitability at a youth justice centre, and remanded him to be sentenced on November 22.