There really isn't one single answer to that question. You may in fact find it cheaper to get Aussie bands. Here's why I think this may be the case:
An Aussie band with a profile high enough to be known in another state (i.e WA) will quite possibly be in the process of, or thinking about touring anyway, in which case they will be funding it themselves (or DCA will be). Meanwhile I'd imagine South East Asian bands wouldn't exactly be rolling in cash so I doubt they'd be able to fund it themselves and would quite possibly need someone to pay their way. The reason we Australian metal bands often have to fund these things ourselves is because we have come to realise that the Australian metal scene is not big enough to do it for us. No touring company is going to fork out for flights, accommodation, van hire, gear hire etc for a band who will inevitably end up playing to 50 people at the Mandarin Club.
So what I'm saying is yes, if you paid, it would be expensive and you'd be silly if you put up huge amounts of cash to venture into a business which you obviously know little about. Now don't take offense to that, all I'm trying to do is give you my opinion. I admire your enthusiasm but it kinda sounds like a pipe dream to me. There is a reason why there are few successful gig/tour promoters, and that's because like any other industry it takes a lot of experience and working your way up from the bottom, and it's a big and RISKY investment to undertake any tour.
I assume you're probably suggesting that you want to organise a big enough festival that will generate the money you need to pay for bands' entire expenses but how would you plan to do that? Lets make a conservative estimate of around $5000 of expenses per band, half a dozen Asian and/or interstate Aussie bands plus maybe another 4 or 5 local bands to flesh it out a bit. What sort of venue would you hope for? Obviously an outdoor one would be aiming too high for a festival of that size. Too big, too expensive, permits, council approvals, all the requirements that go with it like first aid, food and drink stalls, stage rigging, PA hire etc etc etc (just to give you an idea of PA hire, I was FOH engineer at an outdoor concert just a couple of weeks back and you know how much it cost to hire the rig for 1 night? $16 000! It wasn't even a line array, just a standard, adequate outdoor PA). So realistically that's probably aiming a bit high and is why such events are left to the big guys.
Pubs/clubs, more realistic. However the only ones that would be big enough to potentially make anywhere near enough money to fund the whole venture are Nazis when it comes to assurance of numbers through the door. So much so that places like Amps/Capitol will not give you a date unless you're a high profile booking agent booking a high profile international band.
If you did manage to score a decent venue, you'd then have to think about ticket pricing. You're suggesting bringing over a bunch of bands that fuck all people will have heard of. The guys on here and a few other dudes and sheilas in the local scene may have heard them and would maybe be interested in seeing such a gig, but that would amount to absolutely fuck all in a big venue. The rest of the people you see on the street in Trivium or Lamb Of God shirts have probably never been to a local gig before and would probably have no interest in paying to see a bunch of South East Asian bands who they have never heard of, let alone pay for it. A band like some of the ones mentioned above would be no more appealing to your average metal fan than any local band. It's a shame but it's the truth. The general public just don't give two shits about metal bands who they haven't heard of and who aren't on major labels selling shitloads of CDs at JB HIFI.
I don't mean to be Captain Bumyouout but I thought I'd give you something to think about. Unless you have a shitload of cash and you have no intention of seeing any of it again, then I think it's a great idea and I applaud your intentions, but if you're wanting to do this as a business venture, or even just to get a foot in the door, then you might want to think of simpler ways to get started.