Shipping car from USA to NZ and Australia

When they say clean they mean like Swiss clean. NZ Biosecurity has no sense of humour and will order a multi-thousand dollar clean of your car or return to USA at your cost or will incinerate if if they have any concerns. So yes 100% scrub-out and a sensible conversation with Biosecurity (MPI) at the NZ Embassy or phone the Wellington MPI office could save you literally thousands. Cars do enter NZ but usually through authorised dealers so an individual bringing a car in, especially an off-road vehicle will jump straight to the "Maximum Risk" category on the computer system.