Do not know this years figures but last year there were 161 NRL players who were born in NZ. As to how many could/would play for the Kiwis that gets harder as the eligibility rules are somewhat fluid in RL.
Found the numbers here which is off topic from what you asked but interesting.
From Burundi to Cuba, Greece, Jamaica, Latvia, Philippines, Serbia, Sri Lanka, Ukraine and Zimbabwe, the NRL is Australia’s most culturally diverse sporting code.