St John was notified at 9.28pm and sent one rapid response unit and an ambulance.
A spokesperson said the victim was taken to Middlemore Hospital in a minor condition.
Scene of the assault that took place by the playground on William Roberts Road/ Google Maps
Inquiries were ongoing to identify those involved.
Police were appealing for anyone with information to call 105 using reference number 260216/2156, or provide details anonymously via Crime Stoppers on 0800 555 111.
A post by the woman’s flatmate said a week beforehand, a group of teenage boys threw water balloons at a woman reading in the park, and a carload of teenagers set off fireworks to “deliberately” hit a man.