NZRL chief executive Jim Doyle believed the new rule would have a direct correlation with New Zealand retaining talent at an international level.
"It's a really positive outcome. Now it becomes very clear to everybody, whereas previously there was a little bit of ambiguity,'' he said.
"There's no doubt New Zealand create really good rugby league players. There will be players that go through our systems here and go across there at 16 or 17 and end up with one of the clubs there, but they'll now play for the Kiwis rather than play State of Origin because they won't be eligible.
"Which, to me, is the right thing because their origin of state is not New South Wales or Queensland.''
Australian Rugby League commission chairman John Grant said preserving the sanctity of the "unique'' competition was the driving force behind the rule change.
"State of Origin is an incredibly important part of the game and the heart of the concept is a person's state of origin,'' he said. "It is fundamental therefore that the concept is preserved on that basis.''
The cut-off age of 13 was fine by Doyle who said NRL clubs were not targeting players of such a young age.
"If you look at the number of kids that transfer from here across to Australia to play rugby league, they generally don't go at the young age, they go at 15, 16, 17 or 18.
"If they go across at a younger age, generally it's because their parents are moving there for work-related reasons rather than going for rugby league. It's too young to identify, `this person's going to be a star so let's get him across so he can play State of Origin'.''
Other amendments announced yesterday by the ARL commission included shoulder charges being outlawed and the scrapping of the controversial benefit of the doubt system previously used by video referees when awarding tries.