In 1984, Poutasi was the deputy medical superintendent at
Dunedin Hospital. She was awarded a
Harkness Fellowship to study public health administration, health policies, and the quality of health care in the United States. Poutasi was medical superintendent of
Middlemore Hospital, Auckland, until 1987, when she was appointed chief health officer at the Department of Health. In this role, she headed the Health Department's work to implement the recommendations of the
Cartwright Inquiry on cervical cancer as well as New Zealand's efforts to control the spread of
HIV/AIDS. In 1989, she was appointed general manager of the Wellington Area Health Board. Poutasi served as director-general of health at the Ministry of Health from 1995 to 2006, and as chief executive officer of the
New Zealand Qualifications Authority from 2006 to 2020. she left that post in 2022 when the district health boards were replaced with a single agency,
Te Whatu Ora Health New Zealand. She was appointed to the board of Te Whatu Ora at its inception and became chair in 2023, succeeding
Rob Campbell. She resigned that role in April 2024. Poutasi also held governance roles on the board of Network for Learning from 2014 to 2022 and as chair of
Taumata Arowai from 2023 until her death. In December 2022, she wrote a
report on the murder of
Malachi Subecz, criticising the inaction of
Oranga Tamariki leading up to the case. This led to widespread reform within the government to implement preventative measures against the harm of children. ==Personal life and death==