A lightning strike was believed to be behind areas of Queenstown losing power on Thursday morning.
Local power authority Aurora Energy said about 12,000 customers were affected.
Aurora said most affected areas have since had power restored.
"Wow! Loudest thunder ever in Queenstown," one person said on Twitter. "The echoes around the hills made me think it was a landslide."
The NZ Transport Agency Waka Kotahi said there were traffic light faults at multiple locations between Frankton and Queenstown. Motorists needed to apply the give way rules at affected traffic lights, Waka Kotahi said.
MetService's forecast for Queenstown said residents should expect heavy rain and thunderstorms on Thursday morning before clearing, then returning in the afternoon.
