The model has admitted she's "gutted" to back out of her promotional visit but says her health and the health of her unborn child must come first.
Katie said: "I'm devastated I'm not going to be able to make my Australia trip now due to health reasons. I promise I will come soon and it's been a year of planning but I can't risk my babies health and my health is something I can't control.
"Long haul flights have been banned by my dr. Gutted (sic)."
Katie, 35, was scheduled to visit Australia to launch her first couture shoe line, Katie Price – The Gold Collection by Sistar Shoes.
A tweet from the company, however, said: "The launch can wait! Your health and the health of your bubba is most important."
Katie has made no secret of the fact this has been the most difficult of her four pregnancies. She is already mum to sons Harvey, 11, and Junior, 7, and daughter Princess, 6.
In a new interview with Australia's NW, she explained her doctor banned long-haul flying after she began experiencing issues with breathing and started feeling faint.
Katie, who has been on a whirlwind round of promo duties lately, has also spoken about suffering from anaemia and her weight gain this time around.
But even if her Australia trip is off the cards, Katie will have plenty to do back home. Not only is she prepping for the birth of her first child with third husband Kieran Hayler, she recently released her 49th (!) book He's The One, has a new autobiography lined up for later this year, and a brand new perfume, Kissable.
Katie Price chats with Reveal - watch below