All of my local Bunnings in Brisbane sold out of disposable P2 (n95) masks by noon on Sunday. Chemists and auto parts stores as well. Admittedly my neighbourhood is heavily Asian so stocks of those masks would already have been strained given higher general mask use and acceptance, and the recent bushfire smoke issues.

The government normally maintains a reserve of masks. A fair number of those were handed out due to the bushfires (around 3.5 million, source: https://www.smh.com.au/politics/federal/one-million-p2-masks-ordered-as-authorities-respond-to-coronavirus-20200122-p53tqv.html ) and were in the process of restocking, with current numbers remaining of around 10 million. They are stating that in an outbreak, masks will be provided for free, so "Don't panic". I'm not trying to fear monger, just pass on information.

As of today, the national stockpile is being used for doctors when doing consultations for potential cases. Admittedly that's a pretty low number of masks and a very justifiable use, but it does show that the reserve is in use. Source: https://www.abc.net.au/news/2020-01-28/coronavirus-gps-told-to-wear-masks-seeing-suspected-patients/11905414

Stay safe.