England will lose their world No. 1 ranking for the first time since the World Cup if the All Blacks win.
New Zealand will move to the top of the International Rugby Board's ladder for just the second time since the rankings were introduced on the eve of the World Cupeight months ago.
The All Blacks held top spot for only one week, following their World Cup quarter-final defeat of South Africa, but were shunted back to third behind England and Australia when they went down to the Wallabies in the semifinal.
England have held top spot since their World Cup triumph with New Zealand always second but the margin between them has narrowed following English losses in the Six Nations.
The rankings are calculated under a complex system which gives favour to more recent tests and takes into account home ground advantage and the winning margin.
This weekend, sixth-placed Ireland will probably displace South Africa in fifth if they win their clash at Bloemfontein, while in Tucuman, Argentina are in danger of losing seventh ranking to opponents Wales, one place below them.
