A 20-year-old woman was sexually assaulted in the Christchurch suburb of Aranui last month, police say.
The woman said she was walking through Merrington Crescent Reserve around 10pm, on January 6 when the incident happened.
The alleged offender was described as a 30-year-old Polynesian man with a solid build and believed to be wearing a hoody.
Police have spoken to neighbours near the reserve in the hope of identifying the man.
Anyone with information is urged to contact police on (03) 363 7400 or to provide information anonymously through Crimestoppers on 0800 555 111.