Cyco - I've pasted the NOTAM below, and note it is not just a GPS route - Airways NZ have promulgated a temporary FMS or RNAV or GPS route which should allow most operators to transition to the ILS no problems. Obviously the onboard equipment must be "suitably approved" for such use.
I think to promulgate a NDB/DME(ILS) arc would as you say require a flight check and technical survey. Rgds mcdude
P0296/02 - DURING PERIOD OF 'FA' VOR/DME U/S AN ALTERNATE STAR PROCEDURE MAY BE APPROVED FOR SUITABLY APPROVED FMS/RNAV/GPS EQUIPPED ACFT 16 NOV 02:15 UNTIL 08 DEC 03:00 ESTIMATED