The Aids Foundation says those responsible for excluding an HIV-positive child from a daycare centre are being bullies and wilfully ignorant.
The 4-year-old's mother was told he was not welcome at his Whangarei daycare just 48 hours after she told them about his condition.
"[On April 24] my daughter disclosed his HIV status [and] on picking him up that afternoon was told there would be a meeting ... On the 26th [she]... got told, 'Take your son home, we don't want him here'," the boy's grandmother, Angela, told TV3's Campbell Live last night.
The boy contracted HIV at birth from his mother and is on medication. This has reduced the virus to a level undetectable in his blood, thus drastically reducing the chance of it being transmitted to others even when blood is involved.
Angela said her grandson was unsure why he couldn't go back to daycare, describing him as "a little boy who cries every morning because he wants to go and play with his friends and can't understand why".
"If my grandson had leukaemia, a form of cancer, I'd be able to climb on the rooftop and shout it and have all the support in the world. This is a lonely illness," she said.
Aids Foundation executive director Shaun Robinson, whose organisation has had extensive involvement with the child and his family, said the reaction of the childcare centre was not due to a lack of information, awareness or education.
"[The centre has] been very well informed but the sad fact is, the management team don't want to know that there is no risk whatsoever to the other children. They'd prefer to persecute this child and create hysteria in the community," he told Campbell Live.
"It's absolutely appalling. It's a case of wilful ignorance - not just gross ignorance but wilful ignorance - which is leading adults to essentially bully and pick on a 4-year-old boy."
The boy's family were initially reluctant to notify the daycare for fear they would be discriminated against.
"Discrimination is the single biggest issue facing New Zealanders living with HIV today," Mr Robinson said. "We'd like people to be able to disclose that their child has HIV when they enrol at a childcare centre but it's a sad fact that many people don't feel safe or supported enough to do that."
Starship hospital's child healthcare director, Dr Richard Aickin, told Campbell Live there was "absolutely no risk of transmission in the normal childcare environment from a child with HIV who is under good control with treatment".
"It is extraordinarily low - so low we don't consider it a risk."
Mr Robinson, too, said no one was in any danger from the child having HIV. "We'll continue to uphold his right to go to this centre because all children deserve an education, friends, playtime and fun."
The Human Rights Commission said it was unlawful for an early childhood centre to discriminate or exclude a child on the basis of a disability.
The Ministry of Education has also intervened on behalf of the child and his family. It is convening a meeting with other parents and health officials to try to resolve the situation.