The arrangement works both ways and the ATO would be able to get information from the IRD, however, Australian student loan borrowers living overseas don't have to pay. In practice therefore the information flow will be all one way, from the ATO to the IRD.
If you are a New Zealand student loan debtor living in Australia you need to deal with your student loan issues now, before an IRD bailiff or debt collector turns up on your doorstep. Please contact us for advice on all of your options.