Two St John officers and two other people were injured in Te Kuiti after a vehicle hit an ambulance on Sunday.
While transporting a seriously ill patient to Waikato Hospital, a vehicle hit the ambulance at the Ngarongo St and Te Kuiti Rd intersection just before 3:30pm.
St John Ambulance Hamilton territory manager Adrian Gavin said the two ambulance officers were treated at the scene for moderate to serious injuries and a support person travelling with the patient was treated for minor injuries. The original patient's condition is now moderate.
An occupant of the other vehicle was treated for moderate injuries.
"All five patients have been transported to Waikato Hospital by three other St John Ambulance crews that responded to the scene," Gavin said.
"The ambulance has been badly damaged and has been taken off the road."
Police confirmed it received reports of the crash at 3:35pm. It said the road was closed while emergency services were at the scene, but it has since reopened.