The Socceroos' recent struggles - two wins from 11 matches since Ange Postecoglou took over as coach - have seen the team fall outside the world's top 90 nations and behind AFC Asian Cup rivals Jordan, United Arab Emirates, Iraq, Oman, China and Qatar.
Iraq and China each climbed nine places.
The breakdown of Australia's rankings woe:
Australia achieved its highest world ranking of 14th under Pim Verbeek in 2009. That was the closest the Socceroos have come to the world's top ten.
Belgium moved into the top four of the FIFA rankings for the first time on Friday (AEDT) after a strong start to UEFA EURO 2016 qualification.
Marc Wilmots' men moved up a spot from fifth after their 6-0 win over Andorra and a 1-1 draw with Bosnia-Herzegovina put them three points off Group B leader Wales with a game in hand.
Belgium is unbeaten since its FIFA World Cup exit at the hands of Argentina in July and replaces Netherlands, which slips to fifth after disappointing recent results.
Guus Hiddink's side has taken just three points from a possible nine in its qualification campaign, while Uruguay and Spain have slipped to eighth and 10th respectively.
Having surrendered its title as world champion in Brazil, Vicente del Bosque's men were beaten by Slovakia earlier this month with Jan Kozak's side surging 16 places to 24th as a result.
Portugal takes Switzerland's place in the top 10 with the leading three of Germany, Argentina and Colombia remaining unchanged.
Togo is the biggest mover - rising 73 places after breathing life into its CAF Africa Cup of Nations qualification hopes.
Back-to-back 1-0 wins against Uganda this month takes it into 52nd overall with Algeria moving up five places to 15th, making it the highest ranked African nation.
Iran remains the highest ranked in the AFC region despite slipping seven places overall to 51st, while CONMEBOL's top three of Argentina, Colombia and Brazil remains unaffected by the latest results.