Northern Ireland have dropped 25 places in the latest Fifa world rankings from 40th to 65th, with Scotland falling 16 places from 50th to 66th.
England remain in sixth and the Republic of Ireland 34th, while Wales are up one place to 115th.
World and European champions Spain stay in top spot ahead of the Netherlands.
As well as Northern Ireland, Scotland have suffered a disappointing slump on the list following their 2-0 friendly defeat by Brazil.
That result has proved costly, with Craig Levein's side losing their place among the third tier of European seeds.
And the Scots have just two fixtures left before July's 2014 World Cup qualifying draw, adding extra significance to the Carling Nations Cup matches with Wales and the Republic of Ireland.
World Cup winners Spain and runners-up Netherlands hold a respectable lead courtesy of back-to-back Euro 2012 qualifying victories.
Spain beat the Czech Republic 2-1 at home and Lithuania 3-1 away, with the Dutch winning 4-0 in Hungary before beating the same opposition 5-3 at the Amsterdam ArenA.
There is, however, significant movement just below them as Brazil climb two places to third following their friendly win against Scotland.
Germany thrashed Kazakhstan 4-0 but their 2-1 friendly defeat by Australia sees them drop one spot to fourth while Argentina are down to fifth after drawing 1-1 with USA.
Italy, meanwhile, rise two places to ninth thanks to a 1-0 qualifying win in Slovenia and friendly victory against Ukraine.
The 2006 World Cup winners are back in the top 10 after an absence of seven months and their progress comes at the expense of Greece, who have slipped back from 10th to 12th after drawing 0-0 with Poland.
The most significant upward movers in the rankings are Israel - up 25 places to 33rd - and Belgium - also up 25 to 37th.
Montenegro (24th), Albania (50th), Libya (58th) and Antigua and Barbuda (100th) are up to their highest positions since the list was first published in 1993.