Attire for Opera on the Steps?

We will be in Sydney for several days prior to our Tahitian Treasures Cruise on celebrity Solstice and plan on attending a performance of Aida on the Harbor Steps. What is the norm for attire at the "outdoor opera?" I know we will probably see all types of attire from shorts to formal and am not asking what we could "get away with wearing" as is so common on dress code threads, but I would like to know if the ladies wear dresses ( cocktail, long, sundresses?) or pants (dressy, "eveningy," jeans?) and if the men wear jeans, sports jackets with nice slacks or suits?

Thanks!

It's probably not the answer you want but the norm is whatever you want to wear. You'll see casual, smart, beach but probably not a lot of formal. I'd be guided by the weather and then dress down.