Mr Brooksbank, whose salary of over $600,000 per year makes him one of the highest-paid businessmen in the state, said he took the decision in order to spend time with his family.

"It's time for another leader to take the reins and drive what is an ambitious agenda," he said.

"And it's time for me to slow down and spend more time with my partner and my family. Communication technology is great these days, but it's not the same.

"We've positioned the business to be at the forefront of the national transition to renewables, which has the potential to deliver enormous benefits to Tasmania and to Australia."

Hydro chair Richard Bolt said Mr Brooksbank has advised the company that the "time was right for the next stage of his life", moving into semi-retirement to spend more time with family.

"In his time as CEO, he has set a clear strategic path for the business, driving proposals for major new generation and storage projects, delivering strong financial results and championing a significant shift in culture," Mr Bolt said.

Recruitment for Mr Brooksbank's replacement will commence in the coming weeks.

Mr Brooksbank is the latest in a series of senior government employees that have announced departures since the state election.

Department of Premier and Cabinet secretary Jenny Gale resigned on Monday this week, while Premier Jeremy Rockliff's chief-of-staff, Vanessa Field, resigned on Wednesday.