England need to beat Wales by more than 15 points to take Australia's fourth place in the rankings. Should Wales win, they will replace England in fifth. The prize for Italy, should they pull off a shock win over Ireland in Dublin, is a return to the top ten. Ireland's ranking would be unaffected by victory at Lansdowne Road.
Away from the RBS Six Nations, there is a rather tasty derby between Georgia and Russia in the European Nations Cup. Georgia currently lie in 19th in the rankings, four ahead of their rivals. A home win would keep the status quo, but a Russian victory would see them rise to 22nd.
Go to http://www.irb.com/ on Monday to see how the weekend's results affect the rankings.