"We have a young male in a critical condition ... police were on scene."
Inspector Shawn Rutene said both boys were enrolled at the school, and their families were receiving help from Victim Support.
Police said Victim Support was also working with staff, students and other parents. A scene examination was taking place.
Mr Rutene said the CIB was investigating the incident, and police were talking to staff and students at the school.
"There's quite a bit of information to be gathered."
He wouldn't confirm whether a weapon was used in the fight or what the fight was about.
The families of the students in the fight and the school community were going through "a very trying time", he said.
Police at the school were taking photographs outside a classroom in a playground area this afternoon, as people stood at the gate looking on.
A mother who collected her son from school this afternoon said she was "in shock"
"Nobody could tell me anything about it," she said.
"It's a really good school.
"I'm just in shock, I need to take my son home."
Another mother who collected her child from the pre-school on site said she had not received any information about the incident.
A woman who did not want to be named arrived at the school to collect her three grandchildren.
"It's a good school that has the support of the church community," she said.
A resident in a nearby street told APNZ he had seen a school-aged boy being delivered to his parents in a police car escorted by an officer.
Pacific Christian School is a private Year 1 to 8 school, covering primary and intermediate years.
The most recent roll information shows the co-educational school had 84 students, 83 of them Pasifika.
The school's mission is to "glorify God through providing education from a Biblical perspective, in order to bring salvation to students and their families and to effectively prepare students for life, ministry and evangelism in the Asia-Pacific region".
Students, a majority of whom are Tongan, are taught in seminar rooms attached to a large auditorium within the Tokaikolo Church complex.
The most recent ERO report noted that school managers were unable to assure inspectors that they had systems in place for managing all aspects of providing a safe environment for students.
No member of staff held a current first aid certificate at the time of inspection in December, 2012.
The school is run by the Tokaikolo Christian Church -- a well-known Tongan church in Mangere.
The church made headlines in 2012 when its church president came under fire for calling on its congregation to fundraise $100,000 a month.
The scene of the stabbing at Pacific Christian School. Photo / Sarah Ivey
Second stabbing incident
Meanwhile, two teenagers were taken to hospital after another unrelated stabbing at Wickman Way in Mangere at 3.45pm today.
An ambulance spokesman said two patients had been taken to Middlemore Hospital.
One of them, aged in his late teens, had a serious stab wound to the neck, and the other patient had sustained minor injuries.
Neither injury was thought to be life-threatening.
A police spokesman said it appeared there were no other people involved, and they are talking to witnesses.
The investigation is in early stages, with a scene examination taking place, and police said it will take some time to fully establish details.
The incident involved students from Southern Cross Campus, a Year 1-13 school.
Owner of Wickman Way Pricecutter, Jagjit Janjua, said from his grocery store opposite the school gate that he could see crowds of kids leave the school and rush to a nearby carpark.
He said it looked like the whole school was following the fight. He knew something was wrong when a teacher asked him to call police.
"We saw them all go up the road and my wife called police and ambulance.
"The dairy is often packed with students after school, he said.
"They're good kids, well-behaved kids, and we treat them like our own kids."
Wickman Way resident Vaiala Sakaio was going through her afternoon prayers when the fight broke out outside her house on the corner of Wickman Way and Chelburn Crescent.
She saw the fight on the road and some schoolkids jumped over her fence into her garden to get away.
Shortly afterwards she saw a boy lying on the ground outside her house with blood on his shirt, Ms Sakaio said.
"I saw him on the ground and I saw the blood.
"The reason behind the fight is no good."
She wouldn't elaborate on what she thought was behind the fight.
"This is a quiet place.
"There's no trouble," she said.
Ms Sakaio said she had not seen any other fights in the area.
Mangere MP Su'a William Sio called for calm among the community after the first stabbing today.
"I'm in shock by what's happened, that a child has been stabbed while at school. I would just call for calm and for the community to let the police carry out their investigation," Mr Sio said.
"Kids and parents just need to remain calm but also vigilant."
"Our first thoughts are with the victim and with the children and their parents," Mr Sio said.
"It is unfortunate that teachers have to deal with these sorts of incidents. It is of even more concern that the children involved in this instance are primary school pupils.
"However, I would just ask that people hold off from speculation."
