So, are you stating that there is no measurable probationary period where a newcomer, fully qualified as doctor in his/her own European - in this case Spanish - environment, will be working within a hospital or private practice, without collecting payment in return for time there? I would assume it's fair to think that that period involves working under supervision, but that constitutes performing skilled, trained work, does it not?
If you can come up with some official reference to that effect, covering the situation of a fully qualified (in their own country) doctor arriving in Australia with the wish to find a job in their present line of work, that allows them to be paid whilst they are working their way into the Australian system (which I'd think could only be done by spending actual work time on the job in Australia as against sitting at home n Australia reading up on it), please don't be shy about posting it: I will be happy to make a hard copy and give it to my new doctor. If she doesn't take it up, at least it may gain me a brownie point or two! You wouldn't grudge me that, would you?
There is no mystery here - one just goes to the AMC (Australian Medical Council) website...
Just remember that there are two issues in play here...
Firstly one needs to registered to practise - without some form of registration one will not be allowed to work. It is true that proficiency in English needs to be demonstrated in order to be registered, but this evidence ideally should be gathered before leaving one's home country - not after. Basically, for a Spanish national passing an International English Language Testing System "IELTS" (in Spain) would be required.
This registration would likely only be a provisional registration which means that practise under supervision is required.
Whether provisional registration is extended also depends on the medical school from which one has graduated. In the case of Spain I do not believe that any Spanish medical school is excluded by the AMC.
If individuals are trained as specialists in their home country they will be registered provisionally as senior trainees in the appropriate speciality.
Having registration is not a guarantee of a job...one will still need to apply and compete for training jobs.
If one is successful in applying for a job then one will earn EXACTLY the same as any other trainee of the same level of seniority. Individuals are also taxed at the same rate as Australian citizens. (I am not aware of ANY jurisdiction in the Western world where one would or could be forced to work without remuneration in this context.)
How long one needs to practise (and perhaps train) under supervision does depend to some degree on where (which country) one has trained and how experienced one is. Sometimes only six months is required, but sometimes several years may be required as well as fulfilling all the requirements of the local colleges (of Surgeons, Physicians etc) which may also include exams and clinicals.
After one has successfully completed whatever requirements the AMC and relevant college is demanding then one will be awarded a fellowship in the relevant speciality allowing one to practise independently in Australia, which may also include private practise.
None of this applies if one qualifications are NOT recognised by the AMC. In this case no registration will be extended and one will not be allowed to work (as a doctor). I personally know of doctors who ended up in Australia as refugees (and occasionally for other reasons) who hail from countries where the AMC will not recognise their qualifications. In these cases the AMC accepts and understands that they are doctors and will allow them to try and pass the AMC certificate (this is a combination of written and clinical exams that represent the exit standard of Australian medical schools) along with the IELTS. My experience with these individuals is that the AMC certificate is much more a test of one's ability and facility with the English language as opposed to one's medical knowledge - in other words the best predictor of success in the 'medical' exam is actually an excellent standard of English! My personal experience of these kinds of exams in Australia was that they were relatively trivial as far as medical knowledge went.
Passing the AMC certificate in individuals who could not get an initial provisional registration allows them to apply for an internship in Australia. An internship is also a paid position although it also the most junior position that a doctor can occupy.
Bottom line: If one has either provisional or full registration in Australia then one can practise medicine and potentially be employed. If one is employed then one WILL be paid. In fact, the only way one could get an unpaid position (say with MSF or Mercy Ships) is with full registration. These organisations will not accept those doctors with only provisional registration since they can only be employed to supervised (and paid) positions within Australian hospitals.