That's a
VERY different question to your original one
cyco. The answer is that the responsible aviation authority must make a determination that the NDB is close enough to the VOR to be used in lieu. I expect that they would've done so by now, if that was the case - and there would, most likely, be a Class 1 Notam to that effect.
I assume that your reference to the VOR/DME being U/S is really only a reference to the VOR. If the DME is also U/S, all bets are off.
In either event, you're better off doing as
Slasher suggests and fly a procedure from overhead the field. I assume that such an alternative method for joining the Localiser is available there.
In PNG, we have several approaches where either VOR or NDB can be used for the azimuth guidance to, on and from a DME arc.