A burly security guard who faked his licence before parading through the Bourke Street memorial armed with a semi-automatic pistol and wearing tactical body armour was sentenced to 12 months' jail.

Aaron Purves, 27, was wearing a tactical vest, black shirt and cargo pants but no security guard identification when he walked through Bourke Street five days after Dimitrious Gargasoulas allegedly hit dozens of pedestrians with his car leaving six people dead.

Aaron Purves was photographed in Bourke Street five days after the car ramming massacre.

Purves wiped away tears and appeared shocked as he was taken into custody after pleading guilty to 160 charges, most of which related to acting as a security guard without a licence and carrying a handgun without a licence.

But he did not spend long in custody.

Aaron Purves is facing 12 months jail. Jason South

Almost immediately after the hearing, his lawyer lodged an appeal and Purves was bailed to face County Court on February 21.

The court heard that Purves had let his security guard and handgun licence lapse in March 2015 and then falsified both documents so that he could apply for jobs at two different companies.

According to a summary read in court, Purves changed the end of the expiry year from a five to an eight on a photocopy of both licences to dupe Protectcorp Security and Executive Security Solutions into hiring him as a guard.

Documents seized by police showed Purves worked 62 shifts for Protectcorp between November 2016 and February 2017, including on January 25 when he was spotted in Bourke Street mall with a handgun strapped to his right thigh.

Aaron Purves is a former VFL player. Aaron J. Purvis/Facebook

The breach was only reported to police after photos of Purves walking in Bourke Street were published by The Age.

As part of his work with Executive Security Solutions he also trained with a handgun on two occasions at the Oakleigh South Gun Club. Small amounts of xanax and testosterone were seized from Purves' house.

Aaron Purves in the Mall days after a car ploughed into pedestrians. The Age

Magistrate David Starvaggi described the offending as "extraordinary" and said that it struck at the heart of the integrity of the private security industry. He said that by pretending to be a legitimate security guard, Purves was leading a "complete charade of a life".

"You have engaged in a Walty Mitty lifestyle, a fantasy lifestyle. Manufacturing your own licences, manufacturing documents," he said.

Aaron Purves wept as he was taken into custody. Jason South

Mr Starvaggi said that walking through the CBD in the aftermath of the Bourke Street killings armed with a gun was incomprehensible.

"Off the back of what was a extremely raw time for Melbourne citizens, there's you parading around in your tactical gear with a firearm strapped to your side," he said.

He said that it was fortunate that no one in the crowd panicked and that there was no further commotion.

"It beggars belief that no one else saw you that day and, given your lack of identification and any sort of uniform, that a call wasn't made to triple zero," he said.

Purves' defence lawyer, Michael Kuzilny, had argued for no conviction, telling the court that his client had no prior offences and that the behaviour was out of character.

Mr Kuzilny told the court that Purves wanted to work for the Australian Defence Force in the special forces.

Media coverage of the incident had caused Purves great distress, Mr Kuzilny told the court, as photos of him walking in Bourke Street were published in outlets around the world.

He said that Purves had told him he was struggling for money at the time he forged the documents and that getting his licence renewed would have been too expensive.

"He said, 'I was so broke, I just needed some money' and was that context he did something very stupid and deceived everybody and worked without a security licence," he said.

The court heard that both companies who employed Purves have had their licences suspended and are also facing charges.