Zane said it looked as if the person in the red car didn't stop or look for oncoming traffic.
"The front of the red car was hit by the front of the white car."
The white car came crashing through the corner of the fence seconds after Zane dashed out of the way, and the red car crashed through another section of fence.
"I dropped the spade and ran that way," he said, pointing to the house.
Two people, including the pregnant woman, were taken to hospital following the accident about 1.40pm. Neither was in a serious condition and there was no indication the woman's baby was harmed.
Zane rushed to the family in the red car and asked if they were all right before knocking on the front door of his house to tell family members what had happened.
He was unhurt except for a scratch on the leg he got while scrambling out of the way. Zane's aunt Wendy Morgan, with whom he lives, said it was "heart-attack material". She said there was an elderly couple in the white car.
Mrs Morgan was inside the house when she heard "a lot of bangs" and what she thought was a scream. "I actually thought they'd hit somebody."
St John Wanganui manager John Stretton said seven people were involved in the accident.
The 23-year-old pregnant woman, who was a back-seat passenger and hadn't been wearing her seatbelt, complained of body pain but tests didn't indicate there was any harm to her baby.
A 17-year-old male was also taken to hospital with seatbelt bruising.
Mrs Morgan said it was the fourth accident they'd seen on the corner since they moved there two years ago. "We're not surprised," she said.
There used to be judder bars at the intersection, but they were no longer there.
"They don't slow down at all," she said of vehicles coming around the corner.
Mrs Morgan thought a roundabout should be put in to make the area safer.
