Some people could be without power for days or even weeks after the loss of electricity supply to Hawke’s Bay and Gisborne.

Transpower has declared a grid emergency and has a helicopter on standby to investigate the scale of damage.

The outage happened due to flooding at the Redclyffe substation during extreme weather from Cyclone Gabrielle.

The substation is near Otatara Pā Historic Reserve, southwest of Taradale.

Follow live updates of Cyclone Gabrielle here.

The Unison and Eastland networks that distribute electricity to the region are currently down as a result.

“Due to the current situation, we are not able to obtain communications from our substation, but it is likely the Redclyffe substation is underwater,” Transpower said.

“While we cannot currently access the site, we have a helicopter on standby for further investigation when possible.

 “Until we are able to gain access to the substation we will not have a clear picture of how long the region will be without power, but we are advising that the community should be prepared to be without power for days to weeks, rather than hours.”

Transpower said it was working closely with Unison and Eastland to understand the situation and develop a plan to ensure power is returned as quickly as possible.

• Far North could face week long wait for power to be restored
• Power out for about 50,000 households and businesses
• Cyclone Gabrielle: Properties damaged in Far North, state of emergency declared
• Why this storm could be worse: High winds to cause power cuts, downed trees, more slips and surges

Current location of Cyclone Gabrielle

Map: earth.nullschool.net

The state-owned Transpower will update people through our website and social media channels as the situation becomes clearer.

Transpower said there had been brief outage overnight in Taranaki that was quickly fixed.

In Auckland, lines company Vector’s outage map showed swathes of the region were without power on Tuesday afternoon.

Piha has lost power and was cut off from the rest of the country due to slips.

The Vector map indicated most of west and northwest Auckland had unplanned outages. So did eastern parts of Waiheke, and parts of Whangaparāoa.

On the North Shore, some unplanned outages in Windsor Park and Castor Bay were also reported.

In the southeast, some rural and semi-rural areas around Brookby, Clevedon and Whitford were without power early this afternoon.