Where "all" means starting from volume 1, apparently published in 1883.
And "online" means subscription-only, in a LexisNexis kind of way.
If you have a university username and password, you'll find all the NZLRs on the LexisNexis NZ site, via the Law Subject Guide, where you can browse (like a table of contents for each volume) or search (indexed fields and/or full-text searching).
Any questions? Just ask.