"I'm hurt the ministry didn't bother to tell me until this morning," she said.
"If something happened to her I would be kicking myself of the rest of my life.
"She gets a scrape somewhere, it is different - I don't expect to be told about each and every single thing."
But this was a potentially life-threatening situation, she said.
The email, seen by the Herald, confirmed the girl needed to be saved by staff after she mistakenly ended up in the deep end of the swimming pool while at a holiday programme.
The regional manager of Oranga Tamariki in Central Auckland, Anna Palmer, said the organisation was "deeply sorry" that the child's mother was not contacted earlier.
"The social worker's priority was to ensure the young girl received appropriate medical attention and to make sure she was comfortable," Palmer said.
"However, the mother should have been advised as soon as the incident occurred, as it's our policy to ensure that parents and guardians are advised as soon as practicable for significant events such as these."
Palmer said they had made contact with the mother and apologised.
The Auckland mum said the distressing delay had been exacerbated by the fact she was yet to see her daughter, under Oranga Tamariki supervision, since yesterday's incident.
"What must my daughter be going through thinking that her mummy doesn't want her?
"I am really feeling sad. Obviously she needs her mum at this time."
However, the Auckland mum said she was grateful the girl's maternal grandmother had been able to see the child in hospital.
Palmer said in regards to visitation, the young girl expressed that she was too tired after her ordeal for a visit from her mother at the time.
However, Oranga Tamariki was arranging a visit between the mother and her daughter over the weekend.
The mother told the Herald she had been informed her daughter was discharged from hospital today.
She was eager to see the 8-year-old soon.
