The Government is hitting back at protests held in towns and cities against the policy of partial asset sales.
Members of the Aotearoa Is Not For Sale group organised rallies in 16 towns and cities on Saturday.
Up to 4000 people marched from Britomart to Aotea Square in Auckland, where politicians and activists spoke to the crowd.
State-Owned Enterprises Minister Tony Ryall says while he understands some people have concerns about the sales, they are part of a plan to control debt and keep investing in the economy.
Mr Ryall says his party campaigned on the policy at the last election and National was returned with an increased vote.
Legislation permitting the sale of up to 49% of four state-owned energy companies has been passed, and shares in the first, Mighty River Power, will be floated later this year.
Mr Ryall says the Government will retain at least 51% control and expects substantial New Zealand ownership to be retained.
One of the Auckland protest leaders, Miriam Pierard, said she was inspired by seeing so many diverse groups uniting behind one issue. Ms Pierard said the group will continue fighting no matter what happens.
Green MP Julie Anne Genter, who spoke at the Auckland rally, says she believes there are options available to the Government other than selling.
She says the Government's plans are hitting obstacles and there is an opportunity now for campaigners to increase the pressure on ministers.
Energy costs will rise - CTU
Council of Trade Unions economist Bill Rosenberg says the partial privatisation of state assets will push up the price of utility bills.
Mr Rosenberg has compared what state-owned enterprises charge for power to the cost of power supplied by private companies internationally.
He says that, on average, people getting their power from private companies pay $285 more a year.
Mr Rosenberg says very few people stand to benefit if state assets are partially privatised, as less than 10% of the population will be able to afford shares.
