What you need to do when you start work.
You need to start making payments to your Student Loan once you earn over $22,828 a year before tax (or $439 a week before tax).
Repaying your student loan when you have a job - Inland Revenue
You can find information about paying back your student loan on the Inland Revenue website. You can also find the correct tax code. You'll need to give this to your employer so they can deduct your repayments from your earnings.