The security guard, who does not want to be identified, appears to leave the store to see what is happening outside on Bourke Street.

As he steps out onto the street he briefly looks to the left, where the ute is engulfed in a ball of flames. At that moment, Shire Ali can be seen running towards him, before lunging at him with a knife.

The footage obtained by Nine News shows Shire Ali with the knife gripped tightly in his right hand, his arm raised upwards as he repeatedly stabs the security guard in the upper body.

The security guard raises his arms up to shield his body and tries to push his attacker away, but Shire Ali continues to come at him.

Blood splatters can be seen on the marble tiles as the security guard flees from the store entrance and into a nearby corridor.

Shire Ali can be seen chasing him into the area before the footage ends.

SECUREcorp management said he was recovering well and had requested his personal details not be released.

"The officer was hurt in the line of duty and has received medical care as well as support for himself and his family through our employee assistance program," the company said.

"SECUREcorp would like to thank the first responders to the incident, for the support and assistance provided to our officer."