The detective said everyone had a right to be safe and feel safe. "Unfortunately this incident highlights the need for everyone to be vigilant when out exercising on their own."
She emphasised that the detectives working with victims of sexual assaults were highly trained and experienced, and also highlighted the importance of victims speaking up.
"Incidents such as this are of an extremely sensitive and personal nature. The courage and bravery shown by victims of these crimes who report incidents to police should not be underestimated. By speaking up their actions could ultimately prevent someone else becoming a victim."
Police inquiries into this incident are continuing.
Police urge anyone who was in the area at the time of the incident or who recognises the man in the compu sketch to call Christchurch Central Police Station on 03 363 7400.
Information can also be provided anonymously by calling Crimestoppers on 0800 555 111.