Four people have now been arrested, including two 17-year-old men, after a fight in the Auckland suburb of Henderson yesterday.
Police were alerted to a disorder incident at about 3.40pm yesterday.
The group involved began to immediately disperse when police arrived, police said.
They arrested two young people at the time and have referred them to Youth Aid.
A video of the incident posted on social media shows teenagers in school uniform, one of whom points a machete towards another person's throat.
Two weapons were also recovered by police at the scene.
Inspector Stefan Sagar said police were aware of the online footage and were alarmed at the violent behaviour on display.
"Disorder incidents such as this have no place in our community and we will not hesitate to deal with anyone involved.
"There will also be an increased Police presence in the Henderson area in the coming days to prevent any further disorder incidents taking place."
After further inquiries today, two 17 year olds have also been arrested.
Anyone who witnessed the incident is asked to call Henderson Police on 09 839 0600 or call Crimestoppers anonymously on 0800 555 111.