@vivyan12 Bank certificate(s) as I see it is a requirement mainly to prove;
a.) you have the financial capacity to finance your intended activities while in Australia
b.) you have a reason to go back to your originating country.
However, inasmuch as someone is sponsoring your visit, this should not really matter much. I was sponsored/invited and was granted visitor visa with less than PHP20k in all my bank accounts. I did not have land titles or real estate properties submitted.
Just ask your employer for an invitation indicating that they will be shouldering ALL your travel expenses as well as board and lodging during your intended stay. Also attach an employment certification indicating employment details with a note stating that you are allowed to be on leave during that period.
This is just my experience, though... I know of a friend who works at home, with an Australian employer but was denied the visitor visa but that was about 4 years or so ago.