A frustrated shop owner is searching for a 'pervert monkey' frequently stealing underwear from her store in Thailand.

Duanphen Siriarayapan, 62, who runs a clothes shop in the macaque-overrun province of Lopburi, is pleading with authorities to help her catch the thieving monkey named 'Ai Wang'.

She claimed the primate often pilfered underpants from her stall, disrupting her income and scaring her customers.

Officers from the Department of National Parks, Wildlife, and Plant Conservation arrived bringing tranquilisers and cages to her store on April 1.

However, Ai Wang proved elusive and remained hidden until late in the afternoon, prompting the staff to cancel the operation.

They said most of the macaques refused to come out of hiding because of the scorching heat that reached up to 40 degrees Celsius.

Exasperated Duanphen is now offering a 500-baht bounty to whomever catches Ai Wang.

Tha Hin police were also ordered to conduct patrols to help control the rampaging monkeys.

Lopburi has become a popular tourist destination because of its large population of monkeys. The monkeys are mostly long-tailed macaques, and they can be found all over the city, from the temples to the streets.

However, they can also be aggressive, and they have been known to steal food and belongings.