NZQA, The New Zealand Qualifications Authority is planning to add another layer of “English language requirement” for the students who want to continue their Study in New Zealand. Once enforced, students will be required to demonstrate that they meet the English proficiency for each enrolment by an internationally acceptable English language test, such as IELTS.
So some students would have to sit for another international English test prior to each enrolment. For example, if a student enrols in a Level 5 program on the basis of IELTS 5.5 score, the student would have to take another test with IELTS 6.0 score before they can be admitted into a Level 6 program (Unless they meet the criteria through other means)
Further details can be found on NZQA official link : http://www.nzqa.govt.nz/assets/Uploads/2017-Rule-18-proposed-changes.pdf