New Zealanders have been urged to shop around as power prices at the country's largest electricity company rise by up to 14 per cent.

Contact Energy has about 443,000 residential and business electricity customers, many of whom have been told their power will be dearer from April 1.

Rates will go up by an average of 5.5 per cent in 22 regions including Auckland, the North Shore, Northland, Counties, Wellington, Christchurch and Dunedin.

Businesses in the Far North will be stung by a 14 per cent increase, with households facing an 11.8 per cent rise.

Advertisement

Contact spokesman Jeremy Seed said 85 per cent of that increase was due to grid operator Transpower and the local lines company Top Energy increasing costs to retailers.

To upgrade the national grid Transpower will put up its charges from April.

The company has warned customers to brace themselves for increases until 2015, when most projects will be completed.

Lines charges account for around 40 per cent of customer bills.

Mr Seed said while price increases in 10 regions exactly matched increased network charges, rises in Auckland and other 11 other regions contained a slight margin.

Earlier this month Mercury Energy announced a 5.8 per cent increase in power prices for households from April 1, pointing to lines charges as the reason for the increase.

Consumer NZ chief executive Sue Chetwin said some power firms would absorb the increases - and people should shop around to find the best deal for them.

SWITCH TO SAVE
* A government campaign is urging Kiwis to make use of Consumer NZ's Powerswitch website.
* By entering details into the online calculator at powerswitch.org.nz customers can see how much money they could save if they changed power companies.
* 12 per cent more households switched power companies from 2010, with a 74 per cent rise since records began eight years ago.