An elderly woman and a baby have been left with critical injuries after their car collided at a Franklin intersection.
Police and emergency services are at the scene of the crash, where the intersection of Glenbrook and Kingseat Roads will be closed to the traffic for some time.
The elderly woman is reportedly in a critical condition and the baby is in a serious condition.
Both were occupants of the car.
Police are advising motorists to avoid the area.
Patumahoe resident Sandra Caddy said she was working in a shed when she heard a loud bang about 1.50pm.
About a dozen people gathered around the vehicles to help.
"My son went and had a look and he reckons that one vehicle was turning and the other went straight through.''
It was a notorious blackspot for crashes, Ms Caddy said.
"It hasn't been so bad since they put in some electronic 70km/h signs about three months ago, but before that it was probably once every week, every couple of weeks.
"People are speeding through at 100km/h or more on the main Rd [Glenbrook Rd] and the people on the side road [Kingseat Rd] don't stop at the stop sign, basically.''