Lead singer Paul Colman says the trio is "incredibly disappointed" to be unable to perform in Australia at this time.
"We've been looking forward so much to playing together again," Paul says.
"I want everyone to know that we will come back as soon as we can."
PC3, which disbanded in 2004, was supposed to launch its first reunion tour in October with performances in 13 cities including a headline show at Sydney's Black Stump festival.
Black Stump organisers say this year's festival is still going to be an "exceptional event", even without the trio.