The singer was due to play eight shows, starting in Melbourne on April 24, but has been told by doctors to return to New Zealand for "immediate rest and recuperation in order to regain complete health and continue touring for the rest of the year," according to a statement from the tour's promoter.
In the announcement, Lorde told fans: "It breaks my heart to have to postpone these shows as the band and I absolutely love playing to Australian crowds, and it was not a decision we made lightly. I know I need to focus on getting better in order to perform at my best. We'll be with you as soon as we can, Aussies".
Organisers are currently trying to reschedule the Australian tour.
The tour had already been expanded, with an extra date added in Sydney after her first show there sold out.
The 17-year-old has just wrapped two performances at Coachella Festival in the US.
Before that, she played at Lollapalooza in South America, as well as solo shows around the US.
Earlier this month she performed alongside the surviving members of Nirvana as they were inducted into the Rock & Roll Hall of Fame.
Lorde tweeted the news to fans, explaining she has a chest infection and her management team and parents have stepped in and enforced the break from performing.
