I am not sure but definitely ask. You may just have to do a bridging course or something similar. What is your undergraduate in?
Monash seem to have a master preliminary course which does have fees but has commonwealth supported places. To get into that course if you don't have undergrad in science they have these relevant entry requirements:

Graduates with honours in a different field

For graduates with honours in a different field (not regarded as a suitable preparation for direct admission to their proposed graduate studies), or for applicants applying several years after graduation and whose subsequent training and experience is deemed inadequate for direct admission to the proposed graduate studies, or non-university graduates with a diploma or other qualifications, admission may be approved if they are judged to have sufficient aptitude for research in the proposed field and a suitable motivation towards relevant studies.

Other applicants

For those who are not recent graduates but hold a Bachelor's degree and do not meet the entry requirements stated above, but can demonstrate relevant research experience in the field of study to be pursued, a strong case for admission may be made by the head of school to the dean for consideration of admission into the course.