Electricity consumers are being warned their bills will rise by up to 10% this year as power retailers bear the brunt of upgrades to the national grid.
Grid operator Transpower says the higher charges will come into effect from April, and it says customers should brace themselves for additional electricity increases until 2015, when most of its major projects will be completed.
Transpower is refusing to give a figure for the total expenditure but says the projects are essential to a sustainable power supply.
All power retailers spoken to by Radio New Zealand News say price hikes across the country are inevitable, but the exact amount will be determined on a region-by- region basis later this year.
Christchurch lines company Orion has been handed a bill that is 20% up on last year.
The impact on the average household in the region is calculated at about 5% or $45 a year.
In the Far North, residents could be hit with a 10% increase due to a large hike in costs by the local lines company, Top Energy, to retailers.
Electricity retailer TrustPower says however the rise in Transpower charges is not the only reason electricity prices will go up.
Spokesperson Graeme Purches says prices have been artifically low in most parts of the country because of competition created by state-owned enterprises needing to swap assets.
He says the presence of some loss-leading start-up companies has also kept prices down.
Orion facing challenging conditions since earthquakes
Meanwhile, Orion says its operating costs and capital expenditure, at $70 million, are up significantly as a result of earthquake recovery efforts.
Chief executive Rob Jamieson says, at the same time, revenue has fallen because fewer homes and businesses are connected to the network in Christchurch.