The group of six was tracked by surveillance cameras boarding a train headed for Newmarket, where they were met by police officers and taken into custody.
An 18-year-old woman was charged with aggravated robbery and is due to appear at the Auckland District Court tomorrow.
The other five offenders were referred to Police Youth Aid.
Police said they want to speak with the victim to “make sure you are okay and to ensure there is further support in place for you”.
She was described as wearing a grey hoodie with a NASA logo across the front.
“If this is you, or you know who this woman is, please contact Police,” Roberts said.
Anyone with information is asked to call 105 using the reference number 260302/5584.