Police have launched a large investigation into the assault of a 23 year-old woman at Ross Creek in Dunedin last night, Monday 30 November.

A team of over 20 detectives and uniformed staff members are currently involved in the operation.

Police are looking to hear from anyone who may have had sightings of a man in the area any time between 7pm and 10pm.

The man is described as European, tall, of a skinny build and of an undetermined age.

He is believed to have been wearing black shoes, a black t-shirt, and a pair of black ‘Skins' with white writing.

Police know this area is popular with runners and dog walkers, and are asking for anyone who was in the wider Ross Creek area and saw a man matching this description to get in touch with us as soon as possible.

Police are also keen to hear from anyone who saw anything suspicious between the hours of 7pm and 10pm,

Those with information can pass it on to the team by calling the Dunedin Central Police Station on 03 471 4800 and asking for Detective Sergeant John McDade, Officer in Charge: Adult Sexual Assault.

Alternatively, information can also be passed on anonymously via the organisation Crimestoppers on 0800 555 111.

Members of the public are advised that the scene will remain cordoned off today as staff continue to do a search and scene examination of the area. Police are asking people to avoid the area at the current time so they do not compromise any potential evidence.

Police have also spoken to the owner of a light-coloured dog who was in the are at the time, but we are still keen to speak with anyone else who was walking a light-coloured dog in the area around 9pm.

Source: New Zealand Police.