Electricity retailer Trustpower says some people are cheating a billing system designed to protect vulnerable consumers.
The Electricity Commission is reviewing its voluntary guidelines on disconnections to prevent people taking of changes made following the death of Folole Muliaga in South Auckland.
Mrs Muliaga died in May 2007 after the power to her family home was disconnected because of an unpaid bill. The oxygen machine she Muliaga used stopped working and she later died.
After her death, the commission urged power companies to be more cautious about people who would be at risk if their electricity supply was cut off.
Trustpower spokesperson, Graeme Purches, says some customers claiming to need assistance are cheating the system and would like to see more effort by Government agencies to identifying repeat offenders.
Mrs Muliaga's family fears a tightening of rules could put the lives of vulnerable people in jeopardy.
Balance needed, says commission
Electricity Commission chair David Caygill says of the thousands of consumers that have come forward identifying themselves as medically dependent on electricity and vulnerable, only a small percentage actually qualify.
He suspects some people are taking advantage of the system, and says a balance needs to be struck between ensuring no-one in genuine medical need has power cut off and being fair to everyone else.
The New Zealand Nurses Organisation agrees that greater clarity is needed about the rules on cutting off electricity to consumers who are medically dependent on it.
The Nurses Organisation professional services manager Suzanne Trim says the current system could be more robust.
She says nurses want a national registry for vulnerable or medically dependent consumers.
Ms Trim says they are concerned power could still be cut off to homes that need it most.