The 21-year-old world number 46, who missed multiple tournaments this season after contracting coronavirus in April, said she planned to use her absence from Melbourne as an opportunity to recharge.
““This year, in particular, I spent multiple weeks in isolation quarantining, which affected me greatly – both mentally and physically,” Andreescu said in a statement on Twitter.
“In addition, my grandmother spent several weeks in the ICU for a Covid infection, something that really hit me hard.
“A lot of days, I did not feel like myself, especially while I was training and/or playing matches. I felt like I was carrying the world on my shoulders… the collective sadness and turmoil around and it took its toll on me.
“I will therefore not start my season in Australia this year, but will take some additional time to reflect, train, and be ready for the upcoming 2022 tennis season.”
The build-up to the Australian Open, the first Grand Slam of the season, has been overshadowed by speculation over whether men’s world number Novak Djokovic will take part.
It follows a decision by Australian officials to allow only fully-vaccinated players into the country.
The Australian Open went ahead this year but players were forced to spend two weeks in hotel quarantine, crowds were restricted and a five-day snap lockdown was called mid-event.