Solid Energy chairman John Palmer says his replacement will need to commit for at least three of four years to steer the company through partial privatisation.
Mr Palmer has announced he'll step down later this year after almost six years in the role.
His term isn't due to finish until October next year, but he says he'll leave the post early, so a new chairman can oversee the company's growth strategy and preparation for partial privatisation.
Mr Palmer says his available time and workload would not allow him to commit for three or four years.
He says stepping down early has been a tough decision to take given an ongoing commitment to the company and a strong endorsement of the privatisation process.
Mr Palmer has already signalled this will be his last term as chairman of Air New Zealand.
He says he wants to oversee the transition from the current chief executive, Rob Fyfe, to the recently appointed Christopher Luxon, who'll take the reins next year.