Australia's preparations for the upcoming Basketball World Cup have hit a hitch after they were beaten 90-86 by Brazil at Rod Laver Arena.

The Boomers were flat early in Wednesday night's international in Melbourne but after recovering to lead by seven points at three-quarter-time, they were overwhelmed 26-15 in the fourth term.

Josh Giddey (20 points, 10 rebounds) topscored for Australia, while Nick Kay and Duop Reath (10 points apiece) impressed in the frontcourt.

The home side, without injured trio Jock Landale (ankle), Josh Green (elbow) and Chris Goulding (knee), struggled from long range all evening, connecting on 26 per cent of their three-pointers.

Their two most reliable shooters, captain Patty Mills and veteran Joe Ingles, missed 17 of their combined 20 shots.

At the other end the Boomers struggled to contain big Bruno Caboclo (20 points, 12 rebounds), while veteran Vitor Benite drained 5-of-7 of his attempts from downtown, the tourists converting 45 per cent of their three-pointers.

"They've got a lot of bigs who can shoot," Ingles said.

"We need to tidy up ... we'll watch it, we'll get better and get ready for tomorrow."

The 13th-ranked Brazillians were always going to present a tougher task for the world No.3 Boomers, who crushed Venezuela by 56 points on Monday.

The Aussies were sluggish out of the gates, falling behind 9-2 early and trailing 23-13 at quarter-time.

They missed 13 of their first 14 three-point attempts before Kay broke the spell, drilling back-to-back treys to reduce Brazil's lead to two points at half-time.

Mills, after missing his first eight shots, finally swished a triple midway through the third term to give the Boomers their first lead since the opening seconds.

Mills' no-look pass for an athletic Dante Exum slam thrilled the locals and helped propel the Boomers to a 71-64 three-quarter-time lead.

Diminutive point guard Yago Santos sparked a 12-0 burst, capped by 218cm centre Felipe dos Anjos's thunderous dunk, which put Brazil back in front.

Giddey buried a three to tie the scores before Brazil responded with another 8-1 spree to put the match beyond the Boomers.

Australia tackle South Sudan in the last match of the four-team international series on Thursday ahead of the World Cup which starts next Friday.