A school bus heading to Te Papa Museum in Wellington developed a blown head gasket at about 10:30 a.m., releasing fumes that made students feel sick on the motorway.
Local emergency services stopped the bus at the museum, where 19 students reported respiratory and stomach pains. Nine of those children were transported to hospital for treatment.
The 44‑student bus was carrying children to a kapa haka event at the national museum when the incident occurred, according to Radio New Zealand reports.
Emergency responders treated the children on scene and sent the affected nine to hospital, where they are receiving care for the fumes‑induced symptoms.