Organised by parishioner and ex-pupil of St Joseph’s School, Carol Meikle QSM, the event will be hosted by St Mary Star of the Sea Parish and will feature the unveiling and blessing of a commemorative Sacred Heart statue by Bishop Michael Dooley.
There will also be invited guest speakers, a historic display, cake cutting, and a time to meet and greet.
A dedicated researcher into the life and legacy of St Mary of the Cross MacKillop, Mrs Meikle said the 125th anniversary event would help to keep the "personal presence" of St Mary and the Sisters of St Joseph alive in the community.
The founder of the Sisters of St Joseph of the Sacred Heart in Australia in 1866, St Mary spent several months in Port Chalmers in 1898. While there, she established St Joseph’s School, Port Chalmers.
The Sisters of St Joseph maintained a presence in the community from 1898 to 1979.
Through her research, Mrs Meikle has become intrigued by Mary MacKillop as a strong and determined woman, whose work benefited thousands of children.
The saint’s favourite saying was "Never see a need without doing something about it", Mrs Meikle said.
"She believed children must have an equal opportunity for education and dedicated her life to that aim."
Sunday’s celebration will be held from 2pm at St Mary Star of the Sea Church grounds, 38 Magnetic St, Port Chalmers. All welcome.