A Dubbo high school was forced into lockdown after a pair of 16-year-old boys started fighting and one was slashed under the chin with a knife on Wednesday.
Police said the boy who allegedly pulled out the knife and swung it around also sustained knife-related hand injuries.
Other students at Dubbo College South Campus became involved in the fight and five paramedics were deployed to treat young people who needed medical treatment.
"Three male patients all had superficial and minor injuries, while one female patient had no physical injuries," the NSW Ambulance Dubbo duty operations manager Adam Parker told Australian Community Media.
"We transported two patients to Dubbo Hospital and were at the school for about 35 to 40 minutes," he said.
A NSW Department of Education spokesman said when the fight broke out, school staff quickly intervened to calm the brawling students down.
While police and paramedics responded to the incident, the spokesman said other students at the school were kept in their classrooms.
The "incident of inappropriate behaviour" would not be tolerated, the spokesman said.
"Students engaged in such behaviour are disciplined, their families informed and police notified," he said.
"As police are investigating this matter, further comment is inappropriate at this time."
Dubbo police praised staff at the school for their handling of the incident.
Officers went back to the school in the aftermath of the incident to ensure no further conflict broke out and safety was maintained.
Dozens of students were understood to have watched the incident as it unfolded.
Police said charges were expected to be laid at later date.