After a look at the inside of the business Mr Ewers said: "There's cakes, blood and glass everywhere."
He said because of the injuries to the woman, a police serious crash investigator was called to survey the scene.
Whangarei Senior Station Officer Brad Cunningham said as they began to free the woman it was then they realised she was covering a young girl.
"She was entangled in the display case. We cleared a bit of the debris away and found the girl under her," Mr Cunningham said.
The woman could not stand up and firefighters placed her on a stretcher and she was transferred to an ambulance.
"It wasn't a very nice scene when we turned up. It was a terrible shock and the staff are very upset," Mr Cunningham said.
Jenny Gu, who owns the business with her husband Michael Xu,, said she had been changing in the toilet at the back of the shop when she heard a loud bang.
She ran to the display area and saw a car but could see no sign of her 9-year-old son Paul, who had been waiting for her.
"I couldn't see him. I didn't know where he was, I thought maybe he was under the car."
Fortunately he had climbed on to a chair, out of the path of the car.
Ms Gu said it appeared the mother had protected her child by placing her body over her child. The woman had come into collect a cake and was waiting for a staff member to collect it from the fridge at the rear of the shop.
"I think she shielded her and the child is not too injured."
Ms Gu said her husband and a few strong men had pushed the car back off the woman but she was trapped in the glass case.
She said she did not like blood so it was very unpleasant.
"I hope she gets well soon. I feel very sorry that this has happened."