Irish lie fifth in the International Rugby Board official world rankings ahead of Sunday’s test with Australia in Lansdowne Road.
Australia have edged above South Africa into third - a result of the Wallabies beating Italy and the Springboks losing 32-15 to Eddie O'Sullivan's charges last Saturday.
England's demise under Andy Robinson has been confirmed as the 2003 World Cup winners have slipped to a new low of seventh place.
Their latest conquerors, Argentina, whose shock 25-18 victory at Twickenham on Saturday sparked widespread calls for head coach Robinson's resignation, move into the top six at England's expense.
England are reeling from seven successive Test match defeats, and an eighth loss on the bounce when they tackle South Africa next weekend would represent their worst sequence ever in 135 years of international rugby.
England find themselves less than half a ranking point above Scotland, with Wales barely a point further behind in ninth.
World Cup favourites New Zealand occupy top spot, almost eight points clear of France - a team they thrashed 47-3 in Lyon two days ago.
