There are warnings of potential power cuts after a national grid emergency Notice was issued by Transpower.
Transpower warns there's the risk of "insufficient energy offers" for all of New Zealand to meet demand between 7:54am and 9am.
It's being described as a "New Zealand-wide emergency".
"The system operator advises there is a risk of insufficient generation and reserve offers to meet demand and provide N-1 security for a contingent event," Transpower said.
Transpower warns if there is too much demand, it may have to disconnect feeders.
"If participant response across the country is insufficient, the system operator will manage demand to alleviate the grid emergency," Transpower said.
"The system operator may instruct the grid owner to disconnect feeders without further notice to connected parties."
The national grid emergency notice comes as Kiwis wake to another freezing morning, with a cold snap sending temperatures plummeting around the country.
For the second day in a row, Omarama was the coldest place in the country with a teeth-chattering temperature of -9.5C.
But it wasn't the only place seeing negative temperatures with Queenstown and Christchurch clocking in at a bone-numbing -4C. Invercargill and Timaru were in the negatives as well on -3C while Blenheim was -1C.