She said an apology was offered to the Ramanui family the next day but the family are angry over what they say has been a lack of action.
Mrs Ramanui said police were not considering charges against the driver as "there was no basis for inquiry without criminal intent".
"She's not even going to be charged or anything. It's not a criminal offence, yet if I had [left Daniel in a vehicle], I would have been locked up.
"That's why it's frustrating, the only reason anything is getting done is because we spoke out. If we hadn't, it would have just got brushed under the table."
Kawerau police said that after the Ministry of Education investigated, police might be asked to inquire further.
A ministry spokesman said they were continuing their investigation.
Mr Ramanui said police should have begun investigating straight away and not had to wait for a Ministry of Education report.