The accident happened when a seven-seater passenger car carrying a mother and five children collided with a car carrying a mother and a baby around 3 p.m.
Police and fire and New Zealand emergency services responded to the crash, which occurred at the intersection of Itchen and Severn Sts.
It is understood no ambulances were available and police took the mothers and children to Oamaru Hospital for assessment.
Oamaru Sergeant Tony Woodbridge said he was unsure of the severity of any injuries.
“Hopefully these little kids aren't hurt too seriously. They are clearly very shaken and it's just a matter of taking good care of them here at the hospital.”
When asked about hospital transport, he said ambulances “must have been called out in other incidents”.
“I'm not sure what the story is with that.
“But we had a fire and their first aid crew showed up from Oamaru fire station and from Weston fire station. They had added first responders to their crew and my staff were all trained in first aid to varying degrees as well.
“For some reason there wasn't an ambulance available. They have a large area and it happens sometimes.”
Police are investigating and Hato Hone St John has been contacted for comment.