A Taupo woman who died at the weekend following a power cut had been on a breathing machine, police have confirmed.
Fai Deane, 50, died on Saturday at her home on Rifle Range Road.
But lines company Unison Network and retailer Nova Energy both said they had no record that Ms Dean was medically dependent on electricity.
Nova Energy said under regulations, power companies annually send letters asking to be advised of any medically dependent customers.
Unison Networks spokesperson Danny Gough said had his staff known they would have acted.
Mr Gough said they advised all customers who needed an uninterrupted supply of electricity to work closely with their health provider and family to ensure plans were in place if the power was lost.
Detective Senior Sergeant Matt Cranshaw said it had not yet been determined if the power cut caused Ms Deane's death. A post-mortem had been completed and the investigation was continuing.
Unison Networks said 65 Taupo customers on Rifle Range Road lost power for up to four hours after a car hit a power pole.