The Green Party says the Government is wasting money on partially privatising state assets even before a sale has actually happened.
Treasury figures show $24 million was spent on the privatisation process up until the end of last year, and the Greens estimate spending since then will have pushed the figure closer to $26 million.
About two thirds of the cost has been incurred by the Government and a third by the companies involved.
Greens co-leader Russel Norman said the Government has wasted public money on asset sales that the public don't want.
In response, the Government said the level of expenditure is not out of proportion for a major new policy and it will not cut corners.
It said it wants to ensure small investors get the chance to buy shares in the companies and it has to spend money to make sure the sales process is carried out to the highest standard.
Mighty River Power is intended to be the first to be offered for partial sale, but this is delayed while the Supreme Court considers a challenge from the Maori Council.