You don't need to do anything yet. If you get to within just weeks of the expiry of your present visa without a decision made on your Residence application, then at that point you can ask the CO if it is likely it will come through in time. If s/he can't see that it will, then you will need to apply for another temporary work visa. INZ can't issue an Interim visa to keep you legal if the only application in is for residence, but if you have lodged an application for a temporary visa while the previous one is still in force (even if only by a day), then they will do, and if it's for the same kind of visa that you already hold, then the Interim visa will have the same conditions, so you will be able to continue working.
https://www.immigration.govt.nz/new-...isa-conditions