The incident occurred on Otepuni Ave shortly after 8pm. The road is currently closed and business owners have been told to stay inside.
A witness at the scene said Armed Offender Squad police officers and ambulance staff were at the site of a commercial building.
It is also understood a firearm has been found at the scene. At least one person has been taken to hospital.
There are reports on social media that a white tarpaulin can be seen at the scene.
It is understood the gunman has handed himself in, with one person saying, "So everyone in the area is safe now".
Emmergency services attend the scene in Otepuni Ave in Invercargill after a suspected double shooting. Photo / Dwayne CareyA witness said he saw a man pull up on a push bike, put on a balaclava and pull something out from his jacket shortly before the incident.
Police are refusing to provide further details.
The witness said "there were cops everywhere".
"There were cop cars at each end of the cordon, a couple of ambos and a fire engine turned up at one point."
The man said police with torches could be seen searching an area outside the commercial building.
Local Terry Brown said he saw a "chap" bike past, and had an inkling something was off. "It didn't look right. It looked a bit suspicious," he said.
His interest was piqued when the man took off the top he was wearing and put on another, darker piece of clothing before cycling down Otepuni Ave.
Within half an hour the cyclist rode back past his house, still wearing the dark clothing.
