Pol Lt Col Chanan Mekchai, an investigating officer at Patong Police Station, received a report at 11pm that a foreign man had died at Patong Hospital.
He informed Pol Col Korakrit Khanthakrue, Superintendent of Patong Police Station, before attending the hospital.
Police confirmed the deceased was a 58-year-old Australian tourist. Officers reported that the body bore signs of a serious head injury.
Initial investigations revealed that the man was assaulted at about 5pm on Prachanuakroh Rd in Patong. Rescue workers transported him to Patong Hospital for urgent treatment. Due to the severity of his injuries, doctors were preparing to transfer him to Vachira Phuket Hospital for further care.
However, the man succumbed to his injuries at 10:23pm.
Medical staff notified police, who attended the hospital to begin a formal investigation. The body was later sent to Vachira Phuket Hospital for a post-mortem examination to determine the exact cause of death.
Investigators have examined the crime scene and are reviewing CCTV footage from the surrounding area in an effort to identify and apprehend the assailant.
Authorities have also contacted the Australian Embassy to inform officials of the death, police said.
The investigation is ongoing.