Newton-John died on August 8, 2022 after living with breast cancer for 30 years.
The free, ticketed service starts at 4pm at Hamer Hall in Melbourne, while a live stream begins half an hour prior with a personal photo tribute from her family.
The event will feature performers including Delta Goodrem, who played the singer in a 2018 miniseries.
"A force for good. A force of nature. Strong and kind. My mentor, my friend, my inspiration, someone who always guided me ... I love you forever," Goodrem said of the acclaimed singer following her death.
Newton-John moved to Melbourne from the UK at a young age and showed an early passion for performance.
Her big break was playing the role of Sandy in the 1978 film Grease, opposite John Travolta.
The film, featuring hits including You're The One That I Want and Summer Nights, became the soundtrack for a generation and remains one of the most successful musicals of all time.
"My dearest Olivia, you made all of our lives so much better. Your impact was incredible. I love you so much," Travolta posted online following her death.
"We will see you down the road and we will all be together again. Yours from the moment I saw you and forever. Your Danny, your John!"
Newton-John's career spanned more than 60 years, during which she made 28 studio and six live albums.
She won four Grammys with numerous No.1 hits, and sold more than 100 million records.
Newton-John was first diagnosed with breast cancer in 1992 and began fundraising for research and promoting cancer awareness.
A treatment and research hub in Melbourne, the Olivia Newton-John Wellness and Research Centre, opened in 2012 and its services have helped thousands.
In 2019 she was appointed as a Companion of the Order of Australia and also named a Commander of the Order of the British Empire.
She is survived by her husband John Easterling and only daughter Chloe Lattanzi.
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