However, Mr Coffin said the coroner would have to determine how the girl died.
"We don't know if it was suicide or not," he said.
"We don't know what's happened."
Mr Coffin said the school was close-knit, and it was working to help the girl's devastated family.
"It's pretty sad all round obviously."
The girl's funeral will take place tomorrow.
"We are supporting the family ... we've supported them right from the start really."
Specialist help was brought to the school to help explain the tragedy to the girl's friends.
Ministry of Education head of sector enablement and support Katrina Casey said the ministry had been supporting students and staff at the school following the death.
"The death of any child is a terrible tragedy. Our thoughts are with the child's family, friends and school community at this very difficult time," she said.
"Members of our traumatic incident team have been at the school and we will continue to provide support for as long as it is required."
Ms Casey said the circumstances of the death were a matter for police.
A police spokesman said they were called to the incident on Tuesday.
"The young victim was provided with immediate medical care and taken to hospital."
Police have referred the matter to "the appropriate agencies" and no one else was being sought in relation to the incident, the spokesman said.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906 (Palmerston North and Levin)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Samaritans: 0800 726 666 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.
