Six Nations Champions England have been officially named the number one ranked team in the world by the International Rugby Board (IRB), while Ireland are placed third in the first rugby rankings of its kind.
Clive Woodward's England team have been unofficially ranked as the world's best team in a list compiled by a merchant bank, though this is the first time the game's ruling body has issued official rankings.
England, the pre World Cup favourites, head the rankings with a total of 89.95 points out of a possible 100, just ahead of Tri-nations champions New Zealand (89.8) while Six Nations runners-up Ireland command third (83.92).
World champions Australia, who open the defence of their World Cup title on October 10th against seventh-ranked Argentina (80) in Sydney, are fourth (83.81) with France fifth on 82.85 points.
England comfortably accounted for France 45-14 on Saturday to cement their position at the top of the rankings.
The only team participating in the World Cup outside the top-20 are Namibia, who are 25th, behind Portugal, Morocco, Korea, Russia and Chile.
The IRB said the rankings were tested against a database of more than 4,500 international matches dating back to 1871.
Each team was awarded their ranking points on current strength, which stays the same until they play again.
Under the system, matches that are highly predictable will not result in a significant change in a country's ranking points and the only way that teams will make significant moves up the table is if they consistently beat higher-ranked sides.
The IRB said that one rating point difference between countries is equivalent to two points on the field, therefore England, who play 17th-ranked Georgia (63.80) in their opening World Cup match in Perth on October 12th, are expected to win by at least 52 points.
When two teams meet the system also allows for a home field advantage equivalent to three rankings points (six points on the field).
The rankings will be published every Monday.