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.