Is recommendation a must for getting PhD admission in Australia I am new to this community. The discussions here are interesting so I thought may be I can solve one of my queries regarding PhD admissions.

I am in India and I have completed my post-graduation last year from IIT (one of the top engineering institute in India) in research. I have submitted 2 journal papers and 3 conference papers (as co-author) in my post-grad course. Now I am looking for PhD admission in Australia. There is some personal reason for choosing Australia and I don't want to go to other country as of now. meanwhile I am working as a software engineer in an IT organisation.

I have emailed my resume and thesis to professors in Australian universities regarding the PhD vacancies under them. I have not received any reply (positive or negative). I have started wondering whether I am doing something wrong! Is there some other way to get this information and applying for it? Or am I suppose to send more information than resume and thesis, something that I am missing out.

PS: I have not added any sort of recommendation letter yet. I personally feel that my achievements should speak for me.

Thanks for any help in advance.
The short answer is yes. You're not going to get PhD admission virtually anywhere in the world without letters of recommendation. 

But there's something more important: your approach is wrong. You should not start by contacting professors directly. First, find out if the university has a centralized PhD program (these centralized programs are very common in the US, for example). As far as I'm aware, Australian unviersities do not, but if they do then contacting professors individually is just inappropriate and a waste of time; you should apply to join those.

If they don't then you should find out if they're recruiting PhD students. They might have a webpage with a list of possible projects for example. If they do then you want to check those projects out and make sure you're interested before contacting them.

Here's an example of how to get a PhD position in astronomy at the Australian National University. After Googling for this, you should land at this webpage for the RSAA. You can see what topics are being studied there. You can also find a link to a list of potential projects, sortable by the level of study. Restricting the search to only PhD-level projects, the first result as of time of writing is this one on 3D modelling of nearby galaxies by Dr. Brent Groves, with a short description of what is involved. If you like the project, then you can email Dr. Brent Groves with your CV, motivation statements, thoughtful questions about the project (if any), and ask him if he's willing to supervise you. If you've read Dr. Brent Grove's work and have a suggestion for a potential project, you could write that too. If you just send your CV and "thesis" (what's this?) without any apparent knowledge on what Dr. Brent Groves is doing, he's likely to just ignore you.