Single visitor visa wants to go NZ and re-entry to AUS again

[Nami Vanajak]

I'm on a single visitor visa subclass 600 and I'm doing a three months course on the Gold Coast at the moment. I will have about three weeks break from mid June to July. I would like to go to New Zealand for a few days to visit my relatives and come back to continue my study here until completion. For that reason, do I need to apply for the Re-entry permit? Is it possible to re-entry to Australia again?

Thank you