I just came across something relevant here, which says the 30% deposit is an Auckland thing. This page is geared towards migrants, so the whole PR thing may still be true, but it sounds like deposit requirements might be "only" 20% outside Auckland, even for migrants?

https://www.newzealandnow.govt.nz/li...uying-building

"You’ll need a good deposit to get a home loan, as there are currently restrictions on how much of a property’s value banks can lend you. They’re called the loan-to-value ratio requirements (LVR).They mean that borrowers with less than a 20% deposit (30% for property investors in Auckland) may find it more difficult to get a loan."