Yes, they can. Everybody on the planet with an internet connection can.
It's like watching youtube on a pc or smartphone, but on a TV sized screen.
There is nothing in the way like it used to be, when TV had different standards in different regions (NTSC, PAL and SECAM).
Ultraflix is global.
However, it's the content that matters. If you are a Japanese not understanding English, than there is a problem (not for an Aussi though). That's is why there will be need for local adapted accounts that have country based content (with own productions and voice over/subtitling).
As of today, Netflix f.e. will start streaming in Germany, followed by Austria, Switzerland, Belgium and Luxemburg. In France it was launched yesterday with country specific content, next to the original (US) content.
Netflix has already around 50 mln subscribers in 40 countries. Ultraflix will follow this lead now that they have Sony on board (or rather the opposite).
http://www.foxbusiness.com/industries/2014/05...this-year/
http://www.thelocal.de/20140915/netflix-to-la...-this-week