In a social media post today, Southland Fire and Emergency said preliminary investigations into the Awarua Peninsula fire indicated the cause was accidental, "resulting from an electrical event involving a powerline".
The fire broke out early on Thursday and within six hours had gone from covering an area of about 250ha of the Tiwai Point Conservation Reserve to 1200ha with an 18km perimeter.
Multiple ground crews and helicopters were called in to fight the blaze, and crews are continuing to monitor the site for hotspots and flare-ups.
Fire officials today said crews "will continue working until we are confident there are no hotspots. This could take another four to seven days".
They said an investigation was under way and updates would be provided as more information became available.
- APL
