NZ Import Permits valid for 12 months, if they expire before your stuff is in stock then you can ask for them to be re issued as you have the stuff on back order. At least that's what happened in my case. Does mean you have to submit the documents again to get US Export re-approved as these permits only remain valid while your import permit is valid.
I have been waiting since April last year for 2 stripped uppers. Have everything else.
Bookmarks