If you have a look at the compliance plate on a Euro 6  Iveco Daily , it has Australian Euro 4 Complance ,   I would think most NB1 / NB2 vehicles  are the same (category is on your compliance plate)   
For Example , This late Model Euro6 , is Fitted with EGR,  CAT- DPF, Adblue & SCR .  is Certified in Australia as Euro 4  --->   
Road Vehicle Descriptor (RVD1)
 
 AdBlue, DPF . SCR are not a requirement of Euro 4   .  Only thing that is needed for E4 = EGR   .
Pulling all that crap off & keeping EGR still makes it  technically compliant. 
AdBlue Emulators are available online.
To be sure about your particular vehicle it will say Euro 4  / Euro 5  etc on the Australian compliance plate, Enter the  compliance approval number on RVCS Database  
Certification Unit Search