Mighty River is the first state-owned power asset set for a partial sell-down, although the process could be held up by the Waitangi Tribunal decision last week.
The Government is set to make an announcement by Monday about whether it will delay the sell-down. A final decision is needed within three weeks to give Mighty River time to release its prospectus and hold investor briefings before a pre-Christmas listing.
Mighty River reported operating earnings up 4% to $461 million for the year ended June, in line with previous guidance.
Reported profit decreased to $68 million from $127.1 million in the previous corresponding period (pcp), mainly because of non-cash fair-value adjustments.
The company said its underlying earnings of $163 million, stripping out the revaluations, was consistent with the pcp.
A final dividend of $45 million was paid to the Crown, taking the total dividend to $120 million, up 9% on the pcp.
Dr Norman said the annual results revealed Mighty River Power had spent $3.8 million in the year preparing itself for sale.
Of the total, $3.1 million was spent on direct issue expenses.
"The costs of National's asset sales policy just keep on rising. The $3.8 million spent so far by Mighty River has to be paid for by New Zealanders either via their taxes or through higher power prices."
The $3.8 million came on top of $1.3 million spent by the other state-owned companies National planned to partially sell, nearly $1 million dollars so far spent on the Waitangi water rights hearings and $10.5 million on public relations and policy advisers.
"That's just the tip of the iceberg. The Government has a further $96 million budgeted to spend on the sales and there are huge unbudgeted costs such as hundreds of millions for the share giveaway," Dr Norman said.
Mighty River chairwoman Joan Withers said the lift in operating earnings was achieved despite a decrease in hydro generation and was supported by 5% gains in both electricity sales prices and volumes to customers.
The underlying earnings demonstrated a strong operating performance with the company's flexible generation and contract portfolio responding well to changing market conditions, she said.
