Green MP Jan Logie says she won't be standing for re-election in 2023.
In a post on her Facebook page, she made it clear she was not resigning early.
However, as preparation for the next election had already begun, she said it felt time to announce her decision.
In a post on her Facebook page, Logie said she had never believed parliament to be the only place making a change was possible.
But she believed it was important to have people in parliament who carried the voices of marginalised communities and te taiao.
"It's been the hugest privilege to be trusted (sometimes) with the voice of communities I care for deeply," Logie said.
"I am so inspired by the work being done by whānau/hapū/iwi, in our unions and our communities groups and wider communities and the thinking in our tertiary institutions.
"All of your work really has fed my soul and been a beautiful reminder of what is possible."
Logie said she had "absolute confidence" in the Green Party going forward.
She said she was not resigning early - and would continue to work hard in parliament for the Green Party until the next election.
Logie was first elected in 2011.