Funnily enough I was talking about this the other day. On some (extremely rough) calculations on the DXB-AKL vs DXB-SYD-AKL
DXB-AKL- 231T
DXB-SYD-AKL 225T
Like I said, rough calculations, but the 6T of fuel saved is roughly 30 minutes of flying.
Perhaps someone could give more accurate figures