The thing is that if we ban Muslim entry to Australia, whats going to happen in terms of our trade. There will be international outrage, and likely trade or travel sanctions as well.
For example:
1) Many international routes go through Dubai on the way to major European center. What if they do a ban on Aussie passports as well?
Singapore
2) What about the people that works for multinational companies that need to come to Australia to seal a deal?
Singapore
3) What if in response, countries like Indonesian and Saudis put a blanket ban of Australia farming produce ? - Remember the short term ban on live export by the former Labor government? That was one of the reason Allan Jones called Gillard a witch right? Remember the outcry from National MPs? This is going to be worse.
What if the sky falls down? I am sure we can work out a deal with the Malaysians and Indonesians. What do we get from the Saudis?
4) The travel export will also be negatively impacted.
Look, even though I do not agree with alot of far right wing policies, but surely people are not this stupid. And the big business will pull the string on this one.

This is a hypothetical by the NUTTY Greens based upon a sound bite from Trump.