The reigning champions, winners in 1999 and 2003, as well as 1987, have won their last 22 World Cup matches and fast bowler McGrath cannot see a reason for that run to end out in Caribbean.
"I don't say anything I don't believe," said McGrath who is renowned for making predictions regarding series and tournament outcomes.
"If we go and play the way we have I can't really see any team getting close to us. In any Australian sport it seems that attitude is carried right across the board."
Before Australia's 2005 tour of England, McGrath predicted they would retain the Ashes 5-0. In the end they surrendered them 2-1.
But having seen Australia thrash hosts West Indies by 103 runs here on Wednesday, McGrath was in no mood to tone down his comments regarding Australia's prospects.
"We've been so successful over such a long time, we know how to win, what we've to do," said the veteran paceman.
"When you walk on the field you just have to look around you, the guys that are walking with you. There are some amazing players, some of the greats of all time. It does give you a lot of confidence."
McGrath, the most successful fast bowler in the history of Test cricket with 563 wickets, retired from the five-day game after Australia's 5-0 Ashes thrashing of England earlier this year.
This tournament represents McGrath's farewell to top-class cricket. But before he bows out there is every chance the 37-year-old New South Wales bowler will rewrite the record books yet again.
McGrath heads into Saturday's game against Bangladesh here at the Sir Vivian Richards Stadium just one wicket away from equalling Pakistan great Wasim Akram's record of 55 World Cup wickets.
If he does tie left-arm pace legend Akram, he will have reached the milestone in five fewer World Cup matches (33 compared to Akram's 38).
"Guys like Akram are sort of heroes of mine," McGrath said. "He is known as one of the best bowlers of all time.
"To finally go past him, if I get a couple of more wickets, that would be something special.
"It's nice to get little milestones along the way but they are not the be-all and end-all."
Despite his form - he took three for 31 against the West Indies - McGrath said he'd no regrets about his decision to retire and so spend more time with his wife Jane, who has suffered several bouts of cancer, and their children.
"If it was just about playing, I think I could continue all the time," he added.
"It's everything else that goes with it. The travel, the training, you name it, the time away from Jane and the kids.
"So I've been lucky enough to have 14 years at the top level so it's my turn to move on."
Not many will give Bangladesh, who caused one of this World Cup's biggest upsets by beating India, much of a chance at the weekend.
Then again even fewer people fancied their prospects two years ago when - against an Australia side rated 1/500 to win - inspired by a hundred from Mohammad Ashraful they beat the world champions by five wickets in Cardiff.
The most stunning victory in one-day international cricket history saw McGrath's 10 wicketless overs cost 43 runs.