Pol Lt Col Pongpipat Khamchomphu, Deputy Inspector (Investigation) at Thalang Police Station, was notified of the accident at 9:30am.
A rescue unit from Pa Khlok Municipality and rescue workers from the Kusoldharm Foundation Muang Mai unit arrived at the scene, on the boundary between Tambon Thepkrasattri and Tambon Pa Khlok, to find a white Phuket-registered Toyota van with heavy damage to its front.
The driver, Kittisak Chamrung, 23, and his four passengers, all Danish nationals from the same family, were injured.
The four Danish passengers were named as Joakim Pedersen, 55; Ms Sanne Lund Hansen, 47, Paul Valdemar Lund Pedersen, 15; and Agnes Elisabeth Lund Pedersen, just 13 years old.
All four were taken to Thalang Hospital before being transferred to Bangkok Hospital Phuket in Phuket Town.
On the other side of the road was a Ford pickup truck, registered in Bangkok, also with heavy damage to its front.
The driver, Sonthaya Chatratin, 59, had also been injured in the accident.
The extent of any of the injuries suffered in the collision were not disclosed.
The van driver, Mr Kittisak, explained that he had picked up the family from Phuket International Airport and were taking them to Ao Po Pier when the accident happened.
According to the initial investigation by police, the driver of the pickup truck, Sonthaya, was attempting to overtake a car on the one-lane-each-way road when the collision happened.
Both Sonthaya and Mr Kittisak were unable to avoid the collision.
Police are continuing their investigation into the accident.