Can an international student manage his cost of living in Australia if his 4 years PhD tuition fee is waived off by the university?
It is next to impossible. 

I cannot say about Perth, but in Sydney you need at least 15,000 AUD per year to cover your living expenses, assuming you share a room. The minimal salary in Australia is roughly 30,000 AUD per year, and as a low-skilled worker you cannot get a salary much higher than this. This means you will have to work at least a half of your time. Then it is unclear how you will be able to focus on your PhD project and become a good scientist.

In Perth, it is likely to be even worse. Perth is more expensive than the other Australian big cities, although salaries may be higher there as well. 

Getting a job in Australia is not easy. I've read that according to unemployment statistics, those people who get unemployment benefits spend about half a year on average to find a new job. If you are a foreigner, and if your language skills are far from ideal, you are at a considerable disadvantage in the job market. 

On top of that, there may be restrictions on the number of hours you are allowed to work as a student.

However, if your aim is not to become a scientist, but to migrate to Australia, and if you are prepared to face three years of very hard life, it might work for you, but you've got to know what you are doing. If you live in Australia for three years as a PhD student, you may be able to find a legal way to remain in Australia after your PhD program (e.g., by getting a job). Your Australian PhD degree will be a plus. Remember, however, that you cannot become an Australian permanent resident and later get Australian citizenship simply by legally staying in Australia for a certain number of years. I know people who lived in Australia for almost a decade on temporary working visas and were unable to get the status of permanent resident. The common ways of getting that status are to marry a permanent resident or get a long-term working contract whose end date is more that 3 years after the starting date. You have to be a really valuable worker to find an employer who agrees to sign such a long contract with you.

If you want to pursue an academic career, my advice is to find any place in the world where you can get a PhD stipend that will allow you to fully focus on science. If you have a good academic record, this should not be a problem. Many professors have funds on their grants and need good PhD students.