An ITIN can be obtained by completing Form W7 and filling it out by following the instructions in iw7.pdf. These forms can be found by googling “fw7.pdf” and “iw7.pdf” respectively. Then the form can be posted to the IRS. Note it is also possible to use an acceptance agent, however they will typically charge a fee.
In New Zealand, a cost effective way to obtain proof of identity is to take your passport to the issuing authority, i.e. a Department of Internal Affairs office (do not post it there) and ask them to certify it. They will then post it to Wellington (after giving you a receipt) and courier it back to you once the certified copy has been made (this service is free of charge since Apostille Certification is only required if another entity certifies the copy).