A gun-wielding motorcyclist is on the run after holding-up armed security guards outside a Melbourne shopping centre.
The man threatened two Armaguard staff outside a cash van at the Waverley Gardens Shopping Centre car park, in Melbourne's southeast, on Wednesday morning.
They guards were collecting money from a shop inside the centre before it opened.
"They were in a fairly dangerous predicament and they've responded by doing what they're trained to do," Detective Acting Senior Sergeant Simon Polson told reporters at the scene.
The robber wore a dark jacket and black helmet, and fled on a motorbike with a bag and an unspecified amount of cash.
He is thought to have been spotted at Noble Park later in the morning, and detectives want to speak to a caller who reported the sighting to triple-zero.
The security guards were shaken but uninjured.