Mighty River chief executive Doug Heffernan - already one of the highest-paid bosses on the Government's payroll - is to receive a $500,000 bonus after steering the company through its partial privatisation next year.

The company's annual report yesterday revealed that Dr Heffernan had committed to remain with the company, which is to be partially privatised between March and June next year, until the following December.

The commitment was "to ensure continuity of leadership as the company progresses through the potential initial public offering and the next phase under mixed ownership", the company said.

On completion of that term, Dr Heffernan would receive a $500,000 "one-off retention payment".


Chairwoman Joan Withers said the board wanted to ensure "certainty in managing succession planning and continuity of leadership at this critical time of the company's evolution".

The report reveals Dr Heffernan received $1.49 million in the year to June - down from the $1.79 million he got the year before, but more than the $1.2 million paid to Albert Brantley, the chief executive of Genesis Energy, which also published its annual report yesterday.

Green Party co-leader Russel Norman said Dr Heffernan's retention bonus was "incredible".

"Who's going to pay for it? Electricity consumers. It's yet another cost to the Government's privatisation programme."

Dr Norman said the bonus came at a time when many New Zealanders were struggling.

"We've already got a problem with massive inequality, and part of that is because of the overpaying of top-end wages."