Labour MP Darien Fenton will leave Parliament at the next election.
The list MP announced today she would not seek re-election at the September election.
"I'm grateful for the opportunity to have served in Parliament as a Labour MP for nearly nine years,'' she said.
Labour leader David Cunliffe said Ms Fenton had made a significant contribution to the Labour movement in her years at Parliament.
"Darien Fenton has been a strong voice for workers in Parliament, reflecting her former leadership role as the vice president of Council of Trade Unions and head of the Service & Food Workers Union,'' he said.
"This included taking a leading role in the development of Labour's industrial relations policy, particularly in the areas of the Living Wage, and occupational health and safety.''