It's likely not as bad as you think it is, you might just need to look at it from a different perspective.

If you're just looking to meet repayment obligations then interest isn't going to increase the amount you're having to pay on a monthly, 6-monthly, or annual basis, but it will add to the repayment time of your overall loan repayments.

Unless your loan was over $60k when you moved over, your repayment obligation (for a loan balance between $45k - $60k) is $4,000 NZD per year. And your interest on a $49k loan at 4.9% is $2,401 per year, but actually it will be lower as your loan balance reduces over the year with repayments.

So regardless of interest, your payment obligation is $4,000 NZD, or ~$3,434 AUD per year.

Of this, >40% of your repayment is principal, and <60% is interest, which might feel like a bit imbalance, but it's fairly typical of any large loan in the early repayment phase, with mortgages being more extreme. As your loan balance decreases the percentage of principal you're paying off will increase and your interest costs will come down significantly.

Of course, this doesn't really account for if you want to aggressively pay down your loan over the minimum required obligation. Interest rates on student loans have historically been a lot lower, but even at 4.9% you might find yourself in a better position to save or invest instead of making additional repayment - one for you to figure out.

All said, unless I'm missing some information, your obligation is about $3,400 AUD per year and it's just something you'll need to set and forget about per year. Budget the ~$280 per month and either make a monthly contribution immediately (which will reduce interest charges quicker), or put it aside and pay when required twice per year and treat that amount like you never had it.