"He climbed out of his car seat, left the van which was parked on Rangiora St in Castlecliff, and attempted to open the gate to the kohanga reo.
"He couldn't open the gate, and we don't know how long he was standing there in the pouring rain, saturated and crying his eyes out, and he was too distressed to go with the staff member who found him. She had to get another staff member to help," says Ms Whitu.
No one from Te Hunga Rawhitiwhiti told Ms Whitu of the incident at the time but she heard about it from a family member who was at the Castlecliff kohanga reo when it happened.
Ms Whitu then met the head kaiako at Te Hunga Rawhitiwhiti on May 6 and the meeting was attended by all of the kohanga reo staff.
Although the three staff members involved apologised during the meeting, she said she believed the incident was serious enough to warrant dismissal.
"There were eight tamariki on that excursion, with three staff attending them, one bus driver and two bus monitors. I cannot understand how my son could be forgotten and left alone, after his seatbelt had been unbuckled, in a vehicle parked on the main road to the beach.
"The incident was traumatic for my son, but it could have been far worse.
"In my eyes, it is neglect and I don't want this to happen again to any child. It is about the safety of our tamariki."
The kohanga reo called in Aotea Kohanga reo district manager Ruka Broughton to handle the complaint. Ms Whitu says she believed this was a conflict of interest as Mr Broughton is the partner of the head kaiako at Te Hunga Rawhitiwhiti.
One of the staff members on the excursion resigned during a hui with Mr Broughton, although Ms Whitu said the kaiako was back working at the kohanga reo a few weeks later, and is now working elsewhere.
Another of the three staff also later resigned but Ms Whitu said she believes she is also working at another kohanga reo.
"I really think they should all have been stood down immediately, pending an investigation.
"The whole process has been deeply flawed."
She said Mr Broughton suggested that if she was unhappy with the outcome, she was free to remove her two children from the kohanga.
"I let him know that I did not view that as an acceptable outcome, and the safety of our tamariki was of primary importance. I questioned the kohanga's policies and procedures, and the way my concerns were being dealt with by the district manager."
Ms Whitu contacted Te Kohanga Reo National Trust, the national body responsible for kohanga. Representatives of the trust met Ms Whitu and her whanau in Whanganui in July and it was agreed that a mediator be appointed to help resolve the situation.
However, Ms Whitu said a mediator was not appointed and no meeting was arranged until November 4, when two trust representatives met Ms Whitu and her whanau.
Ms Whitu received a letter from the Te Kohanga Reo National Trust Board on Monday advising her that the trust had completed the complaints process.
In the letter chief executive Kararina Cribb acknowledged Ms Whitu's "positive and solution-focused manner" of presenting her complaint.
"It has been a very drawn-out process and I understand her frustration," said Ms Cribb.
"The health and safety of her tamariki is paramount, and she has presented factual information and been transparent."
The recommendations of the trust are that all staff receive professional development to be kept abreast of policies and procedures and that all incidents are recorded and parents advised immediately.
Ms Whitu said she remains dissatisfied with the process and the length of time it took.
"This has dragged on for seven months," she said. "You can't muck around with our children's safety. This was a serious incident that could have ended very badly."
