can a new ipad air bought in australia work on 110 volts?

Yes.

All Apple iPad USB power adapters are designed for use with power sources rated to provide 100V AC to 240V AC at 50Hz to 60Hz. Apple iPad USB power adapters also comply with the IEC/UL 60950-1 and IEC/UL 62368-1 standards for use with power sources rated to provide 115V AC at 400Hz (typically found onboard commercial airlines).

While your Power Adapter will be fully usable when travelling internationally, you may require a simple pin-adapter to allow the Power Adapter to be used with AC power outlets in different countries. For example, a US flat 2-pin connector will require an adapter for the standard Australian power socket. Travel adapters are readily available.

ipads charge by 5volt dc, and the ac chargers apple sell all works from 110 til 240 volts, though a plug converter may be required depending on what country you wish to connect the ac charger