This is the moment an alleged robber threatened gold shop employees with a toy gun in Thailand.

The masked suspect, identified by officers as Wang Wa, 63, had posed as a customer at the store at the Chom Thong Market in Bangkok on November 2.

But while pretending to inspect a gold ring, he suddenly pulled the fake firearm out of his pocket and pointed it at the women, sending them running for safety to the back of the store.

Wang was seen fiddling with the store's doors for several seconds before fleeing onto the streets with the valuable accessory.

However, his escape attempt was thwarted by a brave teenager Narinthorn Ratwongpaisarn, 19, who said he had heard about the robbery and cornered Wang in Bangkok's Soi Chom Thong 16 area.

Speaking to local media, Narinthorn said: 'I was running an errand when I heard about the robbery from the shop assistant. I decided to track down the robber myself, and asked the motorcycle taxi drivers around if they had seen anyone suspicious.

'I was able to track down the thief in Soi Chom Thong 16. He tried to run away, but I knocked him over with my motorcycle. Other passers-by helped to subdue him.'

The heroic youngster said he felt emboldened because he had been told the man's gun was likely fake.

Wang was detained and interrogated by police, who also seized the stolen jewellery and fake gun.

Wang claimed he had been working in the city's Yaowarat 'Chinatown' District for two years, and had carried out the hold-up to obtain money to return to Guangzhou, China.

He further claimed to be homeless, but police said he had previously been seen riding a motorcycle around the area.

Wang was remanded in police custody, with officers preparing to charge him for robbery.

Meanwhile, Narinthorn was given a 10,000 THB (280 USD) cash reward by the gold shop owner for his courageous deed.