In South Korea it's the "North American" accent that tends to be preferred. When I worked there I had two schools begging me to help them recruit Americans and Canadians. One of the schools I didn't bother to help because I wasn't even happy working for them and the other took a lot of convincing to hire the Kiwi they settled on. I had to remind them of the lady's qualifications, how she conducted herself in telephone interviews, and the professional nature of her questions about the school and its materials, etc. They were happy with her (she stayed on for two years) but it was an uphill battle. They actually wanted to hire a guy from Canada without a degree. He simply had the blond/blue eyed/young look and the boss only saw
"no visa hassell and photo op" in the kid.
In Taiwan I worked for one school that would only hire Americans, Canadians and Kiwis. I found that interesting and when I asked the laoban how they came to that preference I was told, "We prefer a north American accent. We had a teacher from Australia and the students couldn't understand him." She talked about nearly losing all of the buxiban's adult students and had to let the guy go because the loss in revenue was not justifying his salary. The school was in a small town, so, desperate without a decent prospect from North America she settled on hiring a Kiwi. The Kiwi left her with a good reputation and enrollment was up. I was the hiree who replaced the Kiwi when he went home, and from what I heard from the students they were happy with the guy. When I was leaving she had me conduct the interviews, and despite having an in-person application from a couple from South Africa - who had teaching experience - the only other buxiban in town had an Afrikaneer and their business was bad so she used that to justify not hiring the couple (despite them being in-country). I liked working for that school but I had my fill of the odd demands for hiring and she ended up using a recruiter.
She eventually found the new teacher:
An Ozzie!
To be honest, I've yet to see any online placements specifying,
"Australian accent preferred," in any way, shape or form. Most seem willing to consider any native speakers.
In nearly a decade of working overseas I never once heard a preference for the
"Australian accent," and only some ill-informed opinions/rationalizations against it (and it was really the exception rather than the norm.) The only prevalent trends were
"North American English preferred." I will site this though: I talked to a surprising number of British nationals who opened buxibans in Taiwan who had an agenda and would only hire fellow nationals.