An alleged “opportunistic” bank heist has left a man with life-changing injuries after homemade explosives used to break into an ATM blew up in his face.

The man and two associates allegedly used homemade explosives to gain access to an ATM at the Queen Victoria Market in Melbourne’s CBD early on Wednesday.

But the device ignited in the man’s face instead, Victoria Police said.

The trio ran away. The injured man fell behind and was found a short time later along an adjoining street.

He was taken to hospital with serious facial injuries and remains under police guard.

Detectives are investigating the alleged theft and arson.

Police don’t believe the incident is linked to a spate of firebombings, ordered by organised crime, on Melbourne’s nightlife venues.

Arson and Explosives Detective Inspector Chris Murray reiterated his warning about fire and incendiary devices being volatile, unpredictable and dangerous in untrained hands.

“This was a targeted and opportunistic attack on an ATM which has left one man with life-changing injuries,” he said.

He appealed for the two other men who fled and left their severely injured associate behind to hand themselves in.

-AAP