Cambodian soldiers claim they caught a turncoat who was allegedly spying for Thailand.

Troops detained the Khmer man, 20, on Wednesday on suspicion of passing on coordinates to Thai forces across the border.

Authorities claimed the young man worked as a 'spotter' pinpointing military targets for Thai F-16 fighter jets and tanks.

Footage shows rifle-wielding soldiers surrounding the alleged spy as he was made to kneel on the ground with both hands cuffed behind his back.

The Cambodian Border Patrol Police (BPP 13th) said he will be charged with treason 'to serve as an example for traitors'.

Officials did not disclose the location of the arrest, which comes days after another suspected spy was arrested in Banteay Meanchey province on December 11.

Territorial clashes flared up earlier this year before a brief ceasefire, but started again this month when Cambodian troops are said to have fired on a Thai engineering team building an access road in a disputed border area.

In the most recent battles, at least 21 Thai soldiers and one civilian have been killed. In Cambodia, the number of military fatalities is believed to be much higher, though regime chiefs have not revealed the actual figure.

Around 600,000 people have been displaced on both sides of the border.

Cambodia's assault has largely been wayward, unguided rockets fired indiscriminately into Thai territory, including an attack on July 24 that killed eight people and injured 13 others. Thailand has used precision drone strikes and fighter jet strikes on military sites.

Former Khmer Rouge henchman and Cambodian dictator Hun Sen has repeatedly claimed that he wants peace and that Thailand is the aggressor.

Thai officials claim the ongoing border confrontations are a threat to 'national security and territorial integrity' and that the areas must be secured.