No it is not true. Firstly the NZ PR does not give any right to live in Australia, only NZ citizenship will and even then only a temporary visa. With Australian PR, you would be granted NZ PR status upon arrival in the country. If you don't leave for over five years then yes you could stay and become NZ citizens, but if you do need to leave before then, well once the initual five years on your Australian visa has expired you are left unable to enter Australia or NZ again as you would not qualify for a return visa for either country.
In a nutshell, it is a very bad idea and if you want to move to NZ, you should apply for a NZ vusa.