The forum that you linked to for Australia is discussing the Department of Immigration and Citizenship. The rules for immigration and qualification for foreigners working or moving to a country will vary by country. Companies can have their own rules for what qualifies as work experience for the purposes of hiring or promotion.
We'll take me as an example. Today, on April 29, 2015, if you asked me how much experience I have as a software engineer, I'd say about 65 months (5.4 years). That includes my internships where I performed software engineering tasks as well as my co-op blocks and my work experience after graduation. If you asked me how many years of work experience I have, I'd answer 68 months (5.7 years), since I'd also include my time as a TA at university. However, just based on that forum you linked to, I would have to answer about 4 years of experience (3 years, 10 months of full-time employment post-graduation).
What matters is what they are asking for, and that depends based on who is asking. Are they asking for amount of time in a certain industry or even sub-field? Are they asking for how long you've held a job? Are they asking for time you've worked after graduation? Depending on who is asking and what they will use the information for will change what you need to provide.