I reckon Qants won’t cancel any flights to China until university starts back in early March. If you look at the pax on board these flights between Sydney to Shanghai/Beijing (especially between late November to early March), I dare say a very large proportion of them are international students.
Once university starts up again in March, there will be bugger all people flying to/from China and Qantas will have no option other than to cancel flights unless they are willing to lose money.