Officers from Phuket City Police Station were notified of the incident at about 5:17pm.
The victim, identified as Wirat Navadech, sustained one gunshot wound to the abdomen and another to the thigh. He was rushed to Mission Hospital Phuket, where he remains under medical care.
According to the initial police report, investigating officer Pol Lt Jaruvit Chuabkhamsook arrived at the hospital to question the injured man and gather details of the incident.
Witness Chakrit Panmee told police that Mr Wirat had called him shortly after the shooting, saying he had been shot by a work colleague, later identified as 50-year-old Prakit Pannarai. Mr Chakrit then went to the warehouse, found Mr Wirat injured, and rushed him to hospital for urgent treatment.
Police have confirmed that CCTV footage captured the incident, showing the suspect chasing the victim inside the warehouse before opening fire. The footage also shows the injured man fleeing the scene before calling for help.
An arrest warrant has since been issued for Prakit, who fled the scene following the attack. Officers have launched a search operation to locate and apprehend him.
Phuket City Police Chief Pol Col Chatree Chukaew said investigators are continuing to gather evidence and are working to bring the suspect into custody.
The motive for the shooting has not yet been disclosed as the investigation remains ongoing.