Those interested in the operations and procedures regarding Australia Post will find it featured on the Web at;
General Post Guide Here Sections 4, 5 and 6 are probably relevant to the discussion here, especially under pg.65 G6.6 "Exclusions from cover" - especially worrying me in the statement;
G6.6.12 – Delivery delays
Australia Post excludes any claim for carriage or delivery delays.*
It seems ya' take yer chances....
* What comes to mind is that line in the 1983 movie "High Road to China" when Patrick O'Malley (Tom Selleck) is held hostage with little chance of escape to the Suleman Kahn (Brian Blessed), saying ; "You hold all the cards". In Australia Post's case, indeed they also seem too! All care, no responsibility.