If you go looking for rugby, you can certainly find it.
There is a bit of local rugby in Thailand, the armed forces have teams, so do a couple of the prestigious schools.
As a generalisation, Thais are a bit more interested in sport than the Chinese that I knew in Hong Kong days.
My rugby club, Eastwood, is plumb in the middle of a part of Sydney which is very popular with migrants from "Asian" countries. As is Gordon, and Northern Suburbs, come to think of it.
Eastwood is moving away from its present base, and the idea is to move a fair way to the north west, where there is a population which is interested in rugby.
Look for Asian faces at Eastwood, Gordon, or Norths games, and you will not see many.
There is a trend in high schools, away from organised sport, certainly away from the traditional organised sports. James Ruse Agricultural High School, the top school in NSW academically, plays very little competitive sport.
People who want their kids to get into academically selective schools, especially those of a non-Anglo background, are very single-minded, the kids get lots of extra coaching, and sport is just not an issue for them.
Bit of a ramble here, but it does seem to me that in general Asians are not a natural audience, either as spectators, or as participants in our game.