Police were called to the scene, a construction site in Soi Phu Yai Din, in Moo 4, Srisoonthorn, just before 8:30am.
Officers arrived to find the victim, identified as 28-year-old Ka Aye, lying lifeless on a steel cutting machine.
He had suffered a deep wound to the right side of his neck and was still holding a red lighter in his hand.
Police arrested coworker 35-year-old Myo Nyein at the scene.
Initial investigations revealed that the two men had an ongoing dispute stemming from a previous incident involving their motorbikes colliding.
The conflict escalated again this morning while they were clocking in for work, leading to a heated argument. During the altercation, Myo Nyein used a knife to slit Ka Aye’s throat, police said.
Mr Ka Aye’s body was taken to Vachira Phuket Hospital while Myo Nyein was taken to Thalang Police Station for further questioning and legal proceedings, police reported.