The young singer has been ordered to return to New Zealand and take some rest "in order to regain complete health and continue touring for the rest of the year."
"In case you missed the announcement earlier, I have had to postpone my Australian shows because of a nasty chest infection and general ill health," she wrote on Twitter.
"I am so so gutted to have to do this but my parents and my team stepped in telling me I needed a break after being non-stop since the Grammys in January. We will 100 per cent be back for this tour (most likely in November) so don't worry about that. I just need time to get back to full gollum girl fitness before I go out playing shows again," the singer added.
She was supposed to start her eight-show Australian tour in Melbourne from May 24, which will now be rescheduled.