Hunter said this was the second incident involving serious violence in public by gang members in the Gisborne and Wairoa area in the past month.
Three Mongrel Mob members aged 21, 28 and 43 and a 37-year-old associate have been arrested and charged with wounding with intent to cause grievous bodily harm and injuring with intent to cause grievous bodily harm.
They will appear in the Gisborne District Court on August 26 with their bail opposed.
A further four gang members are sought and arrests are expected in the next few days.
Hunter said anyone who saw the assault or had phone camera footage was asked to make contact with police.
“Police would particularly like any footage or sightings on between 11.50pm on August 2 and 12.30am on August 3.
“Police are seeking assistance from the community as they are aware of a lot of people who filmed the incident on their cell phones.
“Any piece of information will help us as we work to identify these offenders so that they can be held accountable.”
An online portal has also been set up for people to upload any photos or videos directly to the investigation team. If you have video, or photos, click here.
Alternatively, anyone with information contact the 105 phone service quoting the file number 240803/0149. Information can also be provided anonymously through Crime Stoppers on 0800 555 111.