Technicians are still investigating the cause of a sudden substation fault that cut power to around 500 Powerco customers in Katikati this morning.

Acting Network Operations at Powerco, Dean Stevenson, says the fault occurred at 7.45am and power was progressively restored to all customers by 9.15am.

Photo: File.

No other areas were affected.

Powerco is New Zealand's second largest electricity and gas distribution utility with around 420,000 consumers connected to its networks.

Their electricity networks are in the Western Bay of Plenty, Thames, Coromandel, Eastern and Southern Waikato, Taranaki, Whanganui, Rangitikei, Manawatu and the Wairarapa.

They also have gas pipeline networks in Taranaki, Hutt Valley, Porirua, Wellington, Horowhenua, Manawatu and Hawke's Bay.