Via what is referred to as an "associated document" on the Australia DFAT web site, and a "side instrument" on the NZ MFAT web site, Australia and New Zealand have agreed to exclude ISDS as between each other in the TPP:
3. No investor of New Zealand shall have recourse to dispute settlement against Australia under Chapter 9, Section B (Investor-State Dispute Settlement) of the TPP Agreement.
4. No investor of Australia shall have recourse to dispute settlement against New Zealand under Chapter 9, Section B (Investor-State Dispute Settlement) of the TPP Agreement.
I see the logic here, but I wonder why that logic only applies to Australia and New Zealand, and doesn't extend to others as well.