Hi.
I recently had the same issue on my new D5500 with two
Sigma lenses, one I already owned (70-300 DG APO) and one I had just bought on eBay (10-20DC). Raised this with Nikon and they did advise it was a known issue with V1.01 firmware on the camera and that I should contact Sigma.
Ultimately, because I bought both lenses on eBay, I had to send both lenses to Sigma UK to have the firmware updated at £37.99 each. The good news is that it worked and both lenses now work great.
No idea what Sigma's policy is in Australia, but in the UK if the lens is in warranty they will do this for free. If it's out warranty but you still have proof of purchase (receipt/delivery note) they will do it for £10.
Suggest you get in contact with Sigma Australia and see what they say.
The root of the problem is that when Nikon update their camera firmware, they only test and certify it with Nikon lenses, which I suppose is fair considering the wealth of third party ones on the market which they can't be responsible for.
Good show to Sigma for addressing the issue and offering a solution, but back luck for those, like me, that saved money by buying good quality used lenses and then got stuck with an extra bill for the update.
Good luck with yours mate! Hope you get it sorted.