Links still under construction but here are some good starters:

Medical Association for Prevention of War (Australia) https://www.mapw.org.au/about/

Doctors for the Environment Australia https://www.dea.org.au/

Médecins Sans Frontières (Doctors Without Borders) https://msf.org.au/

Amnesty International (Australia) https://www.amnesty.org.au/

There are many doctor groups and non-medical groups sending medical aid, funds, and sometimes doctors themselves, to conflict zones. One I have supported is Perth Doctors Medical Aid To Palestine https://www.gofundme.com/f/js2a8a-medical-aid-for-gaza