Karyn Hughes sat with a trapped woman, supporting her head and trying to keep her talking, after her car crashed into Kaitoke Hall.
"The poor woman was pretty distressed," Ms Hughes said.
The woman was one of two injured in the two-car crash on SH3 at Kaitoke around 1pm today.
Ms Hughes and her sister Yvonne Reeve were travelling together to their home in Hawera when they came across the crash, at the intersection of SH3 and Concord Line.
"We came around a bend and saw all this wood on the road, and we thought something's not right here," Ms Reeve said.
The wood had fallen off the trailer of one of the cars. Ms Reeve and Ms Hughes pulled over next to Kaitoke Hall to see if they could help.
"I saw the blue car up there against the hall and didn't realise it had been in the crash," Ms Hughes said. "Then I saw the bumper hanging off and saw there was someone in the car."
She was able to get in the back seat of the car and talk to the driver, an elderly woman.
"I was supporting her head, but obviously didn't want to move her. I kept talking to her and asking her questions, to try and keep her alert and talking."
Ms Reeve said a young man had been the first on the scene and had called emergency services.
"He said he was late for work, so he had to leave."
Firefighters had to physically lift the car away from the hall, then used the jaws of life to remove the woman from the car. She was taken out of the car on a stretcher and was wearing a neck brace.
The driver of the other car appeared to have hand injuries. Both women were taken to Whanganui Hospital by ambulance. A hospital spokeswoman said they were in a stable condition.
State Highway 3 remained open in the aftermath of the smash, but traffic was slowed for some time.