She initially promised to run for Parliamentagain, but today said she had decided to stand down after considering her future as an MP during the holidays.
"I have taken the opportunity over the summer break to think about my future and to ensure I am making the right decision in choosing not to seek re-election."
She said she had "loved every minute" of her 11-year career in Parliament.
In her time as an minister, she has held the community and voluntary sector, food safety, senior citizens and women portfolios.
She joins a growing list of National MPs who have signalled their resignation from Parliament, including John Key, Maurice Williamson, Craig Foss, Sam Lotu-Iiga, Murray McCully, Chester Borrows and Jono Naylor.