A doctor on a nearby boat attempted to resuscitate Mr Wells but was unsuccessful.
Sergeant Tod Hollebon said Wells came from a boat with nine people on board, and two others had also been diving.
The two other divers who helped bring the unresponsive diver to the surface were taken to Invercargill Hospital as a precaution.
Wells joined the fire service in 1980 and had served in the Tapanui and Balclutha brigades before joining the Roxburgh brigade in 2007.
He became a station officer in 2009 and was said to have helped improve the operational standards and safety of the brigade.
He also received his gold star for 25 years of service from the fire service in 2011.
The death has been referred to the coroner.
