This is the dramatic moment a have-a-go-hero shopkeeper used his karate skills to disarm an armed thug after having a gun held to his head during a terrifying robbery.

Sibu Kuruvilla, 43, leapt into action when the gunman burst into the store wielding the deadly firearm and demanding cash at around 10pm on Sunday (24/12).

Shocking CCTV footage shows the dad-of-two having the weapon pointed at his face as his petrified young daughters looked on in horror.