More than 12,000 residents in Queenstown, Glenorchy and Frankton were without power after a lightning strike this morning.
By 12pm, Aurora Energy said power had been restored except for about 300 customers in the Frankton area, who were due to have their power restored shortly.
An Aurora Energy spokesperson said the lightning strike hit the Frankton grid exit point and a response crew was on site.
Updates are being made on the Aurora Energy Facebook page.
Queenstown's Lakes District Hospital was this morning running on a backup generator and a DHB spokesperson said the hospital remained operational.
Queenstown Lakes District Council said a slip has closed Glenorchy-Queenstown Rd at Boundary Creek (opposite Pigeon Island) for the day and an update will be provided at 3pm.
MetService said there were 286 lightning strikes over the South Island in a three hour period.
"The thunder that followed it was just amazing it just shook our house ... to the foundations," Queenstown Lakes district mayor Jim Boult told Morning Report.
People in Queenstown have reported hearing what sounded like an explosion before the power went out.
MetService said only modest amounts of rain had fallen but there were nine lightning strikes in just over an hour this morning.
Earlier, power was out to the Skyline Gondola, the Remarkables ski field, Queenstown Motor Park and the industrial area.
An airport spokesperson said the airport had back up generators and had remained operational.
MetService said driving conditions may be hazardous across western areas of the South Island with orange heavy rain warnings in place.
In Milford Sound, 225mm of rain fell in the 24 hours to 10am.