Police want anyone who used a Mount Albert walkway on the day of Lena Zhang Harrap's death to contact them.
A man appeared in the High Court at Auckland last month charged with her murder, and has been granted interim name suppression.
Detective Senior Sergeant Geoff Baber said that despite an arrest being made, it is vital police are able to speak with anyone who used the walkway between Grande Avenue and Summit Drive on the morning of 22 September.
"We know this walkway was frequented by a significant number of people and it's vital that we are able to identify and speak with everyone who used this walkway on the morning Lena was killed," Baber said in a statement.
Police have used CCTV footage to establish there were 29 people who were using the walkway between 7.30am and 10.10am on 22 September, but they said most of them have not yet been identified.
Anyone who used the walkway or was in the immediate vicinity around Grande Ave or Summit Drive on the morning of Wednesday 22 September is asked to contact the investigation team on 0800 DALEYZA (0800 325 399) or to phone 105 and quote file number 210922/0539.