The ambulance driver and a paramedic were taken to hospital suffering from minor injuries
Two ambulance workers on their way to a 999 call were themselves taken to hospital after their vehicle crashed into a lamp post.
The ambulance driver and the paramedic were taken in another ambulance to the Royal Gwent Hospital in Newport, south Wales suffering with minor injuries.
The incident happened in Cardiff Road in the city at 1600 BST on Thursday.
A third ambulance was sent to the original 999 call. Gwent Police are investigating the crash.