"Rest assured everyone is safe," parents and caregivers were told.
Police were speaking with a number of people about the incident and were making inquiries, the spokeswoman said.
Last month a Hamilton high school was put into lockdown after a youth "known to the school" escaped Oranga Tamariki supervision and made their way there.
Fraser High School principal Virginia Crawford told parents the young person presented a "real and present danger to our students and staff".
As soon as the school was informed the youth had absconded, police were called and the school went into lockdown.
Staff and students remained in lockdown as police engaged with the young person, who was then taken back to Oranga Tamariki's care.