A coroner's report on Mangere woman Folole Muliaga says the disconnection of power to her home in May last year played a part in her death.
Mrs Muliaga, 45, died on 29 May 2007 after the electricity supply to her home was disconnected, preventing the use of her oxygen machine.
Mercury Energy, the retail arm of State owned Mighty River Power, disconnected the power because of an unpaid bill of $168.40.
Coroner Gordon Matenga on Tuesday issued the findings of an inquest that lasted two weeks and heard from 20 witnesses.
He found the stopping of oxygen therapy and the stress arising from the disconnection contributed to her death.
Mr Matenga recommended that Counties Manukau Health Board review discharge letters so patients know about their health status and treatment.
The inquest was told that Mrs Muliaga died of complications arising from her morbid obesity and the disconnection contributed to her death.
It also heard there was uncertainty as to whether her family was fully informed about the seriousness of her health and her care requirements.
Family members said they did not know Mrs Muliaga's medical records stated she was not to be resuscitated if her heart stopped.
A spokesperson for the family, Brendan Sheehan, says there is a degree of relief that the inquiry process is over.
Mr Sheehan says Mercury Energy has changed its practices in relation to disconnecting power, but some other companies have not.
Mr Sheehan says the family is likely to seek compensation for her death.