Energy Minister Simon Bridges says he is confident that lines company Vector acted appropriately in the wake of the power cuts in Auckland.
But a full inquiry will be required to investigate who was at fault for putting up to 85,000 residents in the dark over the last two days.
Mr Bridges said this morning it was positive that the number of people without power had now fallen to two or three hundred customers.
Once power was completely restored, an inquiry would need to look what caused the power cut, whether electricity was restored quickly enough, and whether safety measures were followed.
"It's too early to make that call," Mr Bridges said.
"Personally from what I've seen it does look like [Vector] have acted appropriately in the immediate response to this.
"But as I say, I think that's something an inquiry will need to look at."
The inquiry would be either ministerial-led, with help from the Ministry of Business, Innovation and Employment, or led by the Electricity Authority.
It would also estimate the cost of the power cuts to Auckland's economy.