The Christmas Island is a dependency of Australia. The Christmas Island has a flag with yet the national colours of Australia. Why not inspiring from it. This is the design of the Christmas Island flag: http://en.wikipedia.org/wiki/Flag_of_Christmas_IslandThis flag is very current, it was created in 2002.
I have replace the bird buson, the symbol of the Christmas island by the kangaroo, the very representative animal symbol of Australia. There are two versions: on with a white thin line which make a transition from blue to green for having less colour clash and one without it.