"The on-court behaviour displayed by Australia in that game generated huge disappointment by basketball fans and experts," FIBA said in a statement on Monday.
"It is widely suspected that Australia lost that game in order to avoid having to face the reigning world champions USA until the semi-finals.
"Basketball Australia has an opportunity to state its case before FIBA decides whether and to what extent disciplinary sanctions shall be imposed."
Slovenian NBA star Goran Dragic was among the fiercest critics of Australia's performance, taking to Twitter after the match to urge FIBA to take action.
"Basketball is a beautiful sport, there is no room for fixing the game like today Australia vs Angola!! @FIBA should do something about that!" he posted.
With a place in the knockout stages already secured, Lemanis rested his two best performing players of the tournament, star centre Aron Baynes and sharp-shooting veteran Joe Ingles, while giving fellow starters Matthew Dellavedova and David Andersen less than four minutes each.
When challenged post-match on whether his side had contested the match in the spirit of the game, Lemanis was defiant, arguing the heavy tournament schedule demanded he rest his players before the next stage of competition.
"We always, as Australians, compete the right way," he said.
Pressed on how some people would view the loss Lemanis said: "People will make up their own minds.
"There's always going to be speculators. I can't control what people think."
Injured Australian star Andrew Bogut hit out at FIBA's comments and questioned the governing body's consistency.
"So u can naturalize a plyer who has nver stepped foot in a country, but you cant rest players in a game 2 better a draw 4 youself? Ok @fiba," Bogut wrote on Twitter.
"Love it or hate it I have seen this and much more occur many times @fiba tournaments I have played in since 2002 (incl. Juniors)."
Despite missing their two best players, NBA stars Patty Mills and Bogut, Australia had been optimistic of challenging for a first ever World Cup medal.
The Boomers were on course for their first quarter-final appearance in 20 years, leading Turkey by six points with just over a minute to play in Barcelona on Sunday night.
However, some poor decision-making allowed Turkey back into the game and Emir Preldzic buried a three-pointer with five seconds remaining to give the reigning silver medallists a famous win.
Basketball Australia is yet to make comment on FIBA's investigation.
-AAP
