The home team took a 24-6 advantage into the break on a muggy evening at a sold-out Suncorp Stadium in Brisbane and never relented to inflict more pain on their arch-rivals.
Liam Martin and Jack Bostock bagged two tries each, with Bradman Best and Tom Trbojevic also crossing in a fast and furious clash where Australia's fitness in draining conditions proved decisive.
"Any time we come up against you, it's the pinnacle of our game," said Australia skipper Isaah Yeo in paying tribute to New Zealand.
"To our boys, what a special group. I just felt that we had such confidence in what we could achieve, and I was just happy we could have our best performance tonight.
"World champions for the next four years."
The masterclass denied New Zealand their first title since 2008.
That upset - also in Brisbane - was the last time a team other than Australia lifted the silverware.
Since then the Kangaroos have won 23 games in a row at the tournament with Sunday's victory their 13th title from 17 World Cups played since its inception in 1954.
So dominant are they that they have lost just one of 20 Tests in the 2020s.
Kangaroos 'the benchmark'
"Sorry we couldn't get it done tonight," said New Zealand captain James Fisher-Harris.
"But big shout out to the Oz boys. Tough game, brothers. You've been the benchmark for a long time now and we're still chasing. So congratulations to you."
New Zealand performed an emotive haka, eager for revenge after going down 24-22 to Australia in an epic tournament opener over a month ago.
But they were immediately on the back foot, conceding after just 84 seconds.
Harry Grant threw a dummy and found big back-rower Martin who charged over with Cameron Munster adding the extras for a dream start.
After their shaky opening, the Kiwis knuckled down and after a sustained period of pressure centre Casey McLean stepped inside two Australian players to dot down and get them back in the contest.
Jamayne Isaako booted the conversion to move to 227 points - surpassing Shaun Johnson to become New Zealand's most prolific points scorer.
But Australia quickly restored order, with a beautiful offload from Best to Bostock in space who crossed in the corner.
Munster fluffed the conversion but made amends minutes later with a successful penalty to move Australia into a 12-6 lead.
The hosts were well on top and pierced a battered Kiwi defence again as Best finished under the posts before Martin collected his second just before the break with New Zealand tiring.
The second-half started where the first left off, with Australia's Trbojevic over after just four minutes, courtesy of Reece Walsh beating three defenders before the offload.
New Zealand were on the ropes with nothing going their way, including a try given by the referee then denied on review for a knock on.
But New Zealand persisted and Isaiah Papali'i split the defence for a converted try to leave them trailing 28-10 with 13 minutes remaining, only for Australia to hold firm with Bostock grabbing his second as the clock ticked down.