"Hi my loves, unfortunately we all came to realize recently that we need some more time to finish something very important before going back out and doing more shows," she wrote.
"I love you all and I'm so sorry about this :( I promise you I will be back in australia and new zealand before you know it. my love to youuu all."
Eilish, 17, was recently confirmed as one of the biggest names on the Coachella music festival announcement, placed on the second tier below the headliners, Tame Impala, on the Saturday night.
She has released one EP of darkened pop, and made a number of guest appearances as well as duets with another young star, Khalid.
Lowe also picked Tierra Whack, Dominic Fike, DYSN, Conan Gray and Melii to make waves in 2019.