NCEA Level 1 is taken by students in Year 11. For a student to get NCEA Level 1 they must achieve 80 credits from assessments at Level 1 or higher. They must also meet the Literacy and Numeracy requirements, which is a minimum of 10 credits for each.
NCEA Level 2 is taken by students in Year 12. For a student to get NCEA Level 2 they must get 60 credits at level 2 or above and have 20 credits from any level (They can be credits you have already used for NCEA Level 1). They also must have NCEA Level 1 literacy & numeracy.
NCEA Level 3 is taken by students in Year 13. For a student to get NCEA Level 3 they must get 60 credits at level 3 and have 20 credits from level 2, giving a minimum total credit of 80. They also must have NCEA Level 1 literacy & numeracy.