The school's roll has increased by 100 pupils since 2013 when it was 471, with it now being 571, an increase of 13 since 2015.
Mrs Woon said that while they had a few new entrants they also had quite a few new middle school pupils. Many had come from out of town, with a few from Auckland but most from overseas.
"A lot are returning from Australia and there are quite a few immigrants from all over, it's really quite amazing."
She said many of their current pupils came from outside the area that the school was looking to make its zone, but those pupils had nothing to worry about as they were already enrolled.
Ministry of Education head of sector enablement and support Katrina Casey said Otonga Rd Primary School had contacted the ministry earlier this year requesting an enrolment scheme because they were concerned about the risk of overcrowding.
"We've been working with them on the enrolment scheme, and it is expected to be operating by the beginning of term two.
"An enrolment scheme gives certainty to children living near a school, and within the home zone, that there will be room for them at the school.
"We work with boards to determine what a suitable home zone would be."
She said the board was in the process of drawing up a draft zone which they would discuss with the ministry. She also confirmed that children currently attending the school wouldn't be affected by the changes.
Otonga Rd Primary School's roll:
* 2013: 471 pupils
* 2014: 526 pupils
* 2015: 558 pupils
* 2016: 571 pupils