A new report by Massey University for Immigration New Zealand says that since 2000, the number of overstayers has dropped from about 20,000, to just over 10,000.
The university's Paul Spoonley, said the drop in overstayers from the two countries accounted for two-thirds of the overall drop in overstayer numbers.
Professor Spoonley also said reports that the Tongan community has the highest percentage of overstayers is incorrect.
"It's quite a complicated picture and it depends on visa approvals and denials, so there are a number of groups from various countries who overstay particular visa categories. It's not like a league table where Tongans are number one."
Paul Spoonley says initiatives such as the Recognised Seasonal Employer scheme and new systems for monitoring visas are some of the reasons for the drop.
Photo: RNZ/Sara Vui-Talitu