In NZ things like that are deemed to be commercial ops under part 135. This is purely because the raffle is advertised. The work around for a PPL and raffles used to be the cost sharing stuff but CAANZ but the boot into that as well. They determined that the raffle prize was a payment to the pilot and the pilot was the one gifting the raffle money to charity.
I would think that the ruling would be similar in Oz. At the end of the day CASA would not even know about the raffle unless something went wrong.