Transpower is extending an emergency notice over solar storm activity which could interfere with New Zealand's electricity supply.
A grid emergency notice was issued by the New Zealand electricity transmission company on Saturday. The notice was initially valid from 9am until midday but has now been extended to 8pm Sunday.
A Transpower spokesperson told Newshub there had been no power cuts or other issues "and we don't expect there will be".
She added that the notice extension was "a precaution".
It comes as the US National Oceanic and Atmospheric Administration (NOAA) revealed "extreme" (G5) solar storm conditions had been observed for the first time since 2003.
The US NOAA said several strong flares had been observed in the past few days which were "associated with a large and magnetically complex sunspot cluster... which is 16 times the diameter of Earth".
Solar flares happen when "charged particles are accelerated by processes at or near the sun" and "arrive in enough quantity at Earth", the US government agency said.
Otago University physics Professor Craig Rodger described the phenomenon to RNZ as a "solar tsunami".
But he added that this weekend's event wasn't as big as those experienced in 2001 and 2003.
"We have been working with the New Zealand electricity industry in our solar tsunamis research project to look at what would happen if there was an extreme storm for New Zealand, something that was more like one in 100 years, and the conclusion is that is something we need to prepare and be concerned about, this event is something like 50 times smaller than those extreme storms," he said.
Prof Rodger explained that the US Space Weather Prediction Centre (SWPC) showed this patch of activity was set to fade by midnight, but another flare explosion on the Sun has hurled a solar tsunami towards Earth.
The SWPC forecast that burst of activity to arrive late Monday afternoon to early evening.
"So more auroral activity is possible tomorrow too. Once again, not Auckland aurora though."
Those in central and lower parts of the South Island are likely to see aurora activity again overnight but people in the upper North Island are less likely to see it with the naked eye. Find out more on how to view the aurora here.
