COVID-19 set to rear its head for an early impact assessment as three of Australasia's big four banking groups report their interim financial results

Surely there should be minimal impact after just 1 month

One bad year after nine good ones or thereabouts aka the business cycle. This is the opportunity for banks to write-off as much bad debt as possible. Everyone expects it to be a sh1t year so better to lay down the seeds for the nine big bonus years to come.

OZ/NZ are duffrunt, the regulated F.I.RE economy by respective govt. are all secured by overseas single market
Unlike the US, NZ/OZ have robust bail out mechanism, here's interesting links to watch/read during lock down:
https://watchdocumentaries.com/inside-job/
https://www.scoop.co.nz/stories/HL1507/S00101/the-fire-economy-new-zeal…
https://tinyzonetv.to/watch-movie/watch-the-china-hustle-2018-free-5940…
https://www.youtube.com/watch?v=MGrBCtOt4Qs