Emergency services have cordoned off an area of Wellington's Queens Wharf but will not comment on what's happening.
Witnesses at the scene say there is a large police and ambulance presence.
Social media users have reported seeing a body retrieved from the water near Queens Wharf.
Police were alerted to an incident in the harbour at about 8pm.
Ambulance Southern Communication said an ambulance was on its way to the scene at 8.05pm but was stood down.
Police say they are not releasing any information on the incident just yet.