At the Waima Bridge it became clear they were not going to make it all the way to Te Puia.
"I could feel his head when we were still driving to Tokomaru Bay. Mum said she would take me to the police station so the police could drive me faster.
"But once we got there, he started coming out and I was yelling at her to go and get uncle Brian," said Ms Chaffey.
Constable Brian Leach, Ms Chaffey's uncle, delivered the baby in her mother's van.
"Brian was awesome. He started directing people, told someone to get towels and pushed the seat back in the van so I could lie down," she said.
However, the new mum had other plans. She stood up in the van with her head out of the sun roof and guided her baby down into a waiting towel Mr Leach was holding.
"It all happened in about 10 minutes, I realised he was coming at 5.20pm and he was here by 5.30pm," she says.
The 32-year-old says although she was a bit scared, she should have known her newborn would be an early delivery.
"I had a little fear that he was not going to be all right because there were no nurses there or anything. But I just had to stop worrying and push.
"My other son was exactly a week early too," said Ms Chaffey.
Father of the baby Haapi Banks and Miss Chaffey's midwife Lizzie Tamepo managed to arrive just in time to clamp and cut the baby's umbilical cord.
Mother and baby are now resting at Te Puia hospital. Taiariki Chaffey, Miss Chaffey's 10-year-old son, is very pleased with his new yet-to-be-named brother.
"We are just over the moon. He is so cruisy, just sleeping away. Taiariki loves Mummy for giving him a brother.
"We have not decided on a name yet but we are open to suggestions - maybe something to do with being speedy?"
