Sorry was not quite clear before about transit , flying Adelaide - Singapore - Shanghai.

144 hour visa free can be applied upon arrival at the counter at the airport. It counts from 00:00 of the day following your arrival. I saw your itinerary is Adelaide - Singapore - Shanghai which is not eligible for 144 hour visa free. 144 hour visa free is qualified for the passengers travelling from a country to a third country or region via one of the permitted areas of China. If your itinerary is Adelaide - Singapore - Shanghai, then you need to apply for China tourist visa for visiting Shanghai.