Green Party MP Holly Walker will not be seeking a second term in Parliament at September's general election.
Ms Walker, who entered Parliament as a list MP in 2011, said she was withdrawing from the party list for family reasons and that a recent change in family circumstances meant she could no longer juggle being an MP with motherhood.
"We're all safe and well. It's essentially just a change that has caused us to consider our childcare arrangements and reconsider our priorities as a family."
Ms Walker was number 12 on the Green Party's list for the election.
All candidates on the Greens list will move up one spot, with Te Tai Hauauru candidate Jack McDonald moving up into the top 20.