The two huge eyelets make me think it was meant to be permanently attached to something bigger such as a vehicle or artillery piece. Some of the cannons, howitzer's etc had pouches for sights etc. Its amazing what can turn up in Australian stores.
I have seen them sold as Australian jungle binocular covers. The eyelets were supposed to allow a binocular carry strap to be worn with it.
I bought mine for about $15 a piece a couple of years ago...