The Electricity Commission is to hold a public conference next week on the upgrade of the Cook Strait power cable after South Island generators disagreed that they should pay for it.
The commission decided that South Island generators would benefit most from an upgrade of the high-voltage, direct-current link because it allows them to profit from selling electricity to North Island consumers.
It has decided, therefore, that generators alone should foot the bill.
But the largest of the companies, Meridian Energy, says the low hydro lake levels experienced this winter mean North Island generators have benefitted from selling electricity to the south.
National grid company Transpower has proposed to upgrade one section of the Cook Strait link.
A conference will be held in Wellington on 22 September after a request from Meridian Energy for more public consultation.