The VAR has been in the spotlight throughout the tournament in Russia, with a number of rulings made as a result of its use being called into question.
And that was the case again as the Socceroos came from a goal down in St Petersburg to earn a potentially crucial point.
There looked set to be little for either side to shout about in the opening 45 minutes, but Cameroon took the lead in first-half stoppage time through Andre-Frank Zambo Anguissa.
Vincent Aboubakar, linked with Premier League club Newcastle United, wasted a number of chances to make it 2-0 and the Indomitable Lions were eventually made to pay when Mark Milligan levelled from the spot after a hugely debatable decision.
Referee Milorad Mazic initially awarded a penalty and the VAR backed up his assessment despite replays indicating Ernest Mabouka did not foul Alex Gersbach and had instead won the ball.
A decisive goal was not forthcoming for either side, meaning both teams can still progress having claimed one point from two Group B games, although Germany and Chile – who play later on Thursday – remain favourites to do so.
Cameroon started the better of the two sides and went close early on as Aboubakar hit a half-volley wide after being teed up by Benjamin Moukandjo.
Australia grew into a contest starved of quality, as first Tom Rogic curled a free-kick over before Mathew Leckie blazed Gersbach's low cross above the frame of the goal.
The best piece of play came in the 37th minute as Moukandjo and Aboubakar linked up neatly, but the former's effort was aimed straight at Mathew Ryan.
But they did break the deadlock on the stroke of half-time as Zambo Anguissa latched on to Michael Ngadeu-Ngadjui's lofted throughball to flick over Ryan, whose decision to come off his line proved ill-advised.
Two minutes into the second half Australia had a huge chance to equalise but Tomi Juric could only fire over with time and space to pick his spot in the box after excellent work down the right from Leckie.
Australia continued to warm to their task and Rogic saw a goal-bound effort cleared but Aboubakar wasted a chance to put the game to bed soon after, skewing his finish wide from Christian Bassogog's pull back.
And he was punished for his profligacy in highly contentious circumstances as the VAR concluded Mabouka's tackle on Gersbach merited a penalty despite the evidence on offer clearly suggesting otherwise.
Milligan made no mistake in tucking into the bottom-left corner but Cameroon would have quickly been back in front had Aboubakar not sliced over from point-blank range.
The Porto forward was inaccurate with a close-range header 12 minutes from the end of a display he will live to regret if Cameroon cannot ensure progression in their final group game against world champions Germany.