Power was cut to many parts of Northland following a large scrub fire near Whangarei late yesterday.
The fire, which also originally threatened some homes, broke out under the main Northland power transmission lines at about 4.30pm near Holland Rd, Springfield, south of the Whangarei Harbour.
Transpower's corporate communications manager, Rebecca Wilson, said the state-owned power transmission company had switched off the 110,000 volt lines near the fire as a precautionary measure.
She estimated that around 30,000 households, businesses and other power "connections" in Northland were without mains electricity.
"The 110,000 volt network was removed from service due to the need to ensure the safety of those fighting the substantial scrub fire.
Otaika Valley woman Swati Kapoor was swimming at Uretiti Beach when she and other family members noticed the fire.
They watched from a few kilometres away as a pine plantation was engulfed and flames reached nine to 15 metres in the air but were forced to move away as ash began to fall on them.
"It was very scary and dramatic ... we had ash dropping on us like rain and we saw the firefighters evacuating all the houses."
By 7pm Transpower managed to restored power to some areas in Maungataupere and Kaikohe due to the "back feeding" of electricity through parts of the transmission network unaffected by the fire. However power remained out in the majority of areas from Maungataupere north until nearly 8pm.
Nearly 50 firefighters from 12 fire engines and three helicopters were called in to battle the blaze which covered more than 3 hectares and could be seen from many parts of Whangarei.
Some homes were originally in danger and police urged motorists to take as traffic lights were also cut, along with phone coverage in many parts of Northland.
By 7.30pm Fire Service shift manager Megan Ruru said homes were no longer in danger from the fire."The fire isn't controlled, but it's not going to threaten anything. There's a lot of dry scrub on fire."
She said three helicopters were being used but were trying to establish another water supply.
"They were using the water from the sea but because the tide is going out it's getting further to go out."
Metservice meteorologist Ciaran Doolin said it had been dry in the Whangarei area yesterday with light winds and a temperature of 26.4C just before the fire started. Light winds and a high of 29C was predicted for today.