So any kid that arrives here around age 5-6-7 (and lets be honest, they would have hardly any relationship to their country of birth for the most part) and may have played kids football in another country, cannot play any international football for NZ until 23??? That means a few kids can never play in an Olympics. That still just does not seem right. By the time you hit 22 you could well have lived here for 16-17 years and still be considered a foreigner.
and I thought Winston NZ First hated immigrants...
From what I can see it would depend on what FIFA counts as registered Footballer, I agree it sounds ridiculous, but that appears to be the way the rule applies to those who don't have Citizenship by birth (Born here, or Parent/Grandparent), that at the point where they register as a footballer if they don't have that nationality for FIFA purposes they must be in country for 5 years after 18th birthday, it's nuts, but it's clear why the rule was made after some dodgy citizenship occurances.
According to the article (posted earlier) regarding Bernie Ibini, who moved to Australia when he was 1 and had gotten citizenship before he was 10, he had to get clearance from FIFA to represent Australia at age group level. It seems it doesn't have much to do with which country you are first registered for football.