A robber wielding a toy water gun to rob a bank was foiled just two minutes into the botched heist.

The male suspect, referred to as 'A' by police, allegedly tried to raid the financial business in Gijang County in Busan, South Korea, at around 10:58 am on February 10.

He waved around a gun-shaped object wrapped in black plastic and ordered everyone inside to 'kneel down'.

Terrified clerks and customers obeyed as the suspect tried to break into the branch manager's locked office. When he failed, he demanded that the staff stuff his bag with cash.

Taking advantage of A's distraction, a heroic customer named Park Cheon-gyu, 53, then tackled him from behind, allowing the security guards and bank employees to pile on top of him.

They seized his weapon and found it was actually a dinosaur-shaped water gun concealed in black plastic to resemble a real firearm.

Busan Gijang Police Station officers later arrived to haul A into custody, ending his short-lived heist.

A police spokesman said: 'The customers and bank employees who came to conduct business subdued A after a fight. A was arrested just two minutes after entering the bank.'

A bank official said: 'People might find it clumsy or even humorous that a water gun was inside the plastic bag, but at the time, the situation was extremely serious and frightening, leaving women employees and customers in fear.'

Authorities said they were further investigating A's motives for the attempted robbery.