Just looking at the exchange rate charts on xe.com, January 2nd-3rd saw a massive crash to the AU$, against the yen and US$. The yen dropped to 73, while the US$ rate got down to 68us cents... the lowest in ten years. (a 6% crash in a matter of minutes would send many smaller countries into financial crisis or spiral into hyper-inflation as everyone tries to sell off their cash before it is worthless - I'm surprised that I didn't hear anything about it on the news that day)
Both of those rates to the AU$ have mostly recovered in the weeks since, but some speculate that the AU$ will return to those levels during 2019 (we lost about 12% value during 2018 - from 82us cents to 72us cents, so the downward trend is likely to continue).
Other analysts believe that we've reached the bottom of the current trough, and will start the upward part of the cycle again soon.