Prime Minister Helen Clark today said Ms Hartley would give her valedictory speech on Wednesday.
Ms Wall told NZPA she would be sworn in as a MP on March 4.
Ms Hartley has been a MP since 1999. She was elected to North Shore City Council last October. While at Parliament, she has been an assistant speaker.
Labour has been undergoing a rejuvenation process to bring in new blood.
Ms Hartley announced last October she would retire after the summer recess.
Parliament resumed for the year last week.
QNA Comment: Louisa Wall is a member of Rainbow Labour.