The Electricity Networks Association says legislation from 2003 is restricting their ability to get high risk trees away from power lines - and it contributed to last week's huge outage in Auckland.
About 900 properties are still without power a week after a powerful storm battered Auckland, leaving about 180,000 properties without power at its peak.
ENA CEO Graeme Peters, speaking this morning to TVNZ 1's Breakfast, said lines companies have a problem because they are "very restricted by the 2003 tree regulations".
"We've got a problem with the way we manage trees around power lines and we need to fix that," Mr Peters said.
Mr Peters said it's difficult at the moment to get risky or old trees near powerlines removed and called on the government to review the effectiveness of the Act - namely the Electricity (Hazards from Trees) Regulations 2003.
At the moment, trees within half a metre of a power lines must be trimmed back to 1.5m - but that approach is "too prescriptive", Mr Peters said, and said high-risk trees should be considered on a case-by-case basis.
"Is that line supplying power to schools and hospitals?" Mr Peters said.
Mr Peters said underground lines are an option, but are expensive, and that they can actually be more difficult to fix than overhead wires because the faults are hard to find.