Most, if not all, turboprop and jet operators require applicants to have passed the CASA ATPL theory ... ... the 'written examination credit' as a whole should be ... transferrable under the TTRMA.
I think it's true that no authority anywhere will accept a partial or incomplete license for credit. Even the most generous of transfer schemes (such as TTMRA) require a full and current license / rating to be transferred. To do otherwise does degrades the assumed safety & competence level of the applicant quite a lot.
For example, the NZ written exams might be more theoretical in nature, but rely on the practical test to sort out real-world problems. Australian exams might be more practical, not having a flight test. If this were true, you couldn't mix NZ written exams with the Australian issue requirements.
Private operators might be required by law to only employ CPL-qualified pilots, and then voluntarily restrict themselves by only dealing with applications "with ATPL written credits". But that's not at all the same as a government voluntarily degrading a stricter requirement to a less strict one.
Just another hoop to jump through really.