The national team coach has selected a youthful 30-man provisional squad ahead of next month's tournament in Brazil, where Australia will meet talented South American side Chile and the two 2010 finalists, holders Spain and three-time runners-up the Netherlands.
And while plenty has been made of the scale of the task facing Group B's underdogs, Postecoglou - with January's Asian Cup and future World Cup qualifying campaigns in mind - has chosen to focus on the positives of the invaluable exposure to top-level football his players are set to receive.
"(It's) a massive challenge but also a massive opportunity to lay some solid foundations moving forward," he told FFA TV.
"We are going to take a young group across ... the majority of them, this will be their first World Cup, facing the best in the world.
"From my perspective, there's an enormous opportunity there, because coming out of this World Cup, after having faced the best, there'll be no excuse for us not to continually progress beyond there, there should be no barriers for us.
"I'm sure we're going to have some major obstacles on that road, but again, as I said, a tremendous opportunity for us."
Australia play a farewell friendly against South Africa in Sydney on May 26, before a warm-up clash with Croatia on June 6.
Postecoglou has flagged the second match as the final opportunity to fine tune his tactics ahead of their tournament opener against Chile on June 13, while the meeting with Bafana Bafana is being viewed as a potential morale booster two days before the flight to South America.
"Every game is important for us in the lead up," he said.
"Croatia, the importance of that will be for different reasons because it'll be a sort of trial run for us for the World Cup. The South Africa game is a chance for us to leave our shores with some positive vibes coming off everyone, be that the supporters, the players, everyone involved.
"We need a strong performance, we really want to get on that plane with the players feeling that game against South Africa went well and certainly there's some things we're going to try there that are earmarked for the World Cup campaign."