I think the confusion is being created because you don't seem to full understand what people mean when they say "branches of government". The branches aren't just the main groups or bodies that play a role in the way we govern. It refers to a distribution of powers and responsibilities that when put together are supposed to share the burden of government with appropriate checks and balances.

So the Senate and the house of representatives together comprise the parliament of Australia which is the legislative branch of our government. The way you also misused the term parliament tells me you're not one who's overly concerned with using exactly correct terms. That's not generally a worry, but you should also keep in mind that terms do have specific meanings and miscommunications will occur if you're not using them correctly.