I personally do not care for it (or the fifth New Zealand flag proposal on which it is based), but have to admit that the basic design passes vexillological muster.
Why don't I like it? To begin with, it looks like a signal flag. The colors and shape don't seem to mean anything, but are fairly generic flag design elements. This is a shame, in view of all the indigenous symbols that might have been incorporated.
The New Zealand version seems to reference a red hill. I have no idea what this alludes to (I thought Australia was the one with the red hill...?), but it was apparently popular enough to bump the design into the top five, so I assume there is something behind it. Your design copies the NZ proposal--which is ironic, since one of the problems with the current NZ flag is that it looks so much like Australia's. (But perhaps this one won't be chosen for NZ. In fact, the existing flag is polling at about 75 percent support.) Anyway, if one flag copies another, there should really be some sort of cultural or political reason for it.