I am Argentinian, travelling from Papua New Guinea to Argentina. I'll arrive to Sydney on the 19th of June at 18:55 pm and I am boarding my next flight on the 20th of June at 11:45 am. I am not going to leave the airport.
Sydney (SYD), Cairns (CNS), Gold Coast (OOL)
Do not operate on a 24 hour basis and overnight stays are not permitted. Passengers transiting overnight will need an appropriate visa for Australia to leave the airport to access overnight accommodation.
So you will have to leave the airport, and for this reason, you will need a transit visa (or a regular visitor visa).