The Grammy Award-winner was scheduled to perform at the newly-constructed Resorts World Theater in November as well as in January and February of next year, AFP reported.
"I'm heartbroken by this," she said in an Instagram post on Tuesday. "My team and I have been working on our new show for the past eight months, and to not be able to open this November saddens me beyond words."
"Now, I have to focus on getting better... I want to get through this as soon as I can," she added.
In a statement, Dion said she's been "experiencing severe and persistent muscle spasms which are preventing me from performing."
Doctors are evaluating and treating her, she said, but in the meantime her symptoms "are prohibiting her from participating in the ongoing rehearsals for the new show."
Her "Courage World Tour" -- the first without her husband-manager Rene Angelil, who died from cancer in 2016 -- is still expected to resume in March.
After kicking off in September 2019, the tour had been suspended through the Covid-19 pandemic.