My contact hours vary between 25-33 hours a week at university, (this is at the higher end of hours) you then have to do your own independent learning (e.g anatomy) and do other assessment or group work. You can work part time, although anything more than 10 hours during the working week is a bit of a stretch. This is only relevant for the first two years of the course which are on campus, after that you are hospital based (if we're talking about monash)
The workload to pass in year one is relatively cruisey, you'd have to be organised, but the concepts are not all that difficult, although anatomy learning lends itself to those who are interested and do the extra reading. Year 2 is pretty full on, some more difficult concepts, lots of off campus placement, including a 2-week rural placement.
The hospital based years is another step up. Two 18 week semesters where you have to balance clinical based learning with independent study, part time work might be hard to organise or may not wish to bother at all with it. The best strategy to support yourself is to earn your idependence during the first two years of the course, and get youth allowance for the clinical years, it makes for a less stressful financial situation
Post grad goes like this
MBBS (undergrad degree) 5 or 6 years ---> Compulsory internship --> 1 year --> Resident Medical Officer 1-3 years
During your residency (RMO) is when you apply to specialist colleges (including GP) for further training, this can range from another 3-6 years (3 for GP, 6 for alot of the surgical specialties)