UPDATED 6.04pm Green MP Kevin Hague has announced he is to leave Parliament to take up a new role as CEO of Forest and Bird.

LISTEN ABOVE: Kevin Hague spoke to Larry Williams

Green Party co-leader Metiria Turei said “Kevin has made a huge contribution to the Green Party and the green movement and we are truly sorry he is leaving Parliament."

Party co-leader James Shaw said Mr Hague has been an excellent advocate for Green policies over many years.

"He has worked tirelessly and effectively, for the Green Party and with other political parties. We will miss his passion and his wisdom." 

Mr Hague was elected as a Green MP in 2008 and stood unsuccessfully to become Green Party leader last year.

He previously worked in the health sector as Director of the AIDS Foundation and Chief Executive of the West Coast District Health Board.

He was also active in the anti-apartheid movement and in Maori and gay rights activism.

Mr Hague’s achievements in Parliament include "championing" accountability and workplace health and safety in the wake of the Pike River disaster, forcing culture change at ACC, helping establish Nga Haerenga the New Zealand Cycle Trail, said Mr Shaw.

He was also responsible for leading the successful campaigns for marriage equality.

Ms Turei said although the party is sad to lose Kevin, they're delighted Mr Hague is able to continue his contribution to the environment at Forest and Bird.

"We know he will be a fantastic leader for this New Zealand icon,” said Ms Turei.  

Forest and Bird spokeswoman Kate Graeme said Mr Hague has an excellent grasp of conservation opportunities and challenges, both in New Zealand and overseas.

She said he has been active at many levels of the conservation sector and is already familiar with the organisation's values and focus.

Ms Graeme said his experience in both politics and senior management will open a new chapter in the organisation's history.

With Mr Hague’s resignation, Barry Coates will come into Parliament as the next person on the Green Party list.

Ms Turei said Mr Hague's successor will bring extensive experience in social justice, climate change and Pacific work.

Mr Coates was the executive director of Oxfam NEw Zealand for 10 years.

"He will be an important new voice in Parliament and we look forward to working with him,” said Ms Turei.

Mr Coates also brings business and management experience, as well as governance roles with Fairtrade Australia NZ and the Council for International Development.

He is currently working on trade issues, and is developing a sustainability programme at the University of Auckland Business School.