BSPT (British Standard Pipe Thread) is similar to NPT except for one important difference. The angle across the flanks of threads (if you sliced the fitting in half long-ways and measured the angle from root to crest to root) is 55 degrees instead of 60 degrees as it is for NPT. Thus an NPT male will fit into a BSPT fitting or vice versa but they will not seal.
There is another difference, with most of the pipe thread sizes - except for 1/2" and 3/4" sizes [both 14tpi], BSPT and NPT have different thread pitches! So except for those two sizes, the fittings won't engage for more than a couple of turns.
NPT plugs and fittings are available in Australia, from industrial suppliers of hydraulic/pneumatic equipment.
