Energy industry and investment analysts expect Mighty River Power will attract much interest from investors.
As part of its programme of partial asset sales, the Government is to sell up to 49% of the company by the end of next year.
Mighty River Power owns a mix of hydro-electric power plants along the Waikato River, as well as geothermal plants and a gas-fired station in Auckland.
Energy industry consultant Brian Leyland says although many of its assets are old, they generate strong earnings.
He also says says partial privatisation will force Mighty River Power to publish its books regularly.
Equity research analyst Jason Lindsay says there will be interest from institutional investors, but the Government has indicated its focus will be on retail investors.