A witness said a northbound ambulance in Cumberland St received damage to its front in the crash, at the intersection of Cumberland and Frederick Sts, about 9.20am today.
A car was on its side at the scene and police were talking to several witnesses.
A police spokeswoman said a lane was blocked and inquiries were ongoing.
In a statement, Hato Hone St John's district operations manager Southland-Otago said the ambulance was responding to an incident using lights and sirens but was not carrying any patients.
After the collision, another vehicle was dispatched to respond to the initial incident, Pauline Buchanan said.
Three ambulance officers were assessed at the crash scene by two other crews.
They were uninjured, but another patient at the scene was assessed as being in a moderate condition, she said.
‘‘Hato Hone St John takes the health and safety of its patients and ambulance staff very seriously and is providing support to those involved,’’ Ms Buchanan said.
The damaged ambulance was now off the road for repairs and St John was assisting police with the investigation, she said.
A Fire and Emergency NZ spokesman said no one had been trapped in the collision and two appliances from Dunedin and Willowbank stations attended.
