A woman was sexually assaulted near the Maitai River last night after socialising at a Bridge Street bar.
She left the bar with a man she had been socialising with between midnight and 1am walking down Collingwood St and on to Riverside Drive.
The man has sexually assaulted the woman and then left. Police were alerted shortly after.
Police say the woman has been traumatised by the incident. She has undergone a medical examination and is receiving specialist support.
The offender is described as in his early 30s, possibly Maori but with pale skin and a beard.
Police would like to speak to anyone with information relating to the investigation or who has seen people in Riverside Drive between the hours of midnight and 1am.
Please call Nelson Police Ph 5463840. Information can also be given by calling Crimestoppers Ph 0800 555 111.