John Palmer is quitting as chairman of state-owned Solid Energy because at the age of 65 he is unwilling to stay on and see it through to partial privatisation.
Mr Palmer, who is also chairman of Air New Zealand, took up a strong public position in calling for the partial privatisation of state-owned companies and he welcomed the government's plan to sell down stakes in electricity companies and Solid Energy.
State Owned Enterprises Minister Tony Ryall announced Mr Palmer's departure from Solid Energy on Friday.
"While it is disappointing to lose such a senior director, I wish to recognise Mr Palmer's commitment to the company since his appointment in 2006, and the developments the company has made under his leadership," Mr Ryall said.
Mr Palmer said Solid Energy was not likely to be partially privatised until late next year or early 2014 and the company needed a chairman to commit all the way through, The Press reported.
"Just the pressures on my time and the determination to lower my own workload means that despite the passion I have for the company I am just not willing to commit at my age for another three to four years."