Didn't someone on this forum say that Jetstar Asia flight crew get an overall better package ex SIN than in Australia?
Anyway I doubt that wages are everything. Singaporeans are paid triple what Malaysians are paid and probably 10 times more what Indonesians are paid. If wages were the be all and end all, every company operating in Singapore would have moved out by now. I mean just across the causeway, (its barely 2km long) the rents are 1/3 that of SIngapore, the labour costs are a third too.....
However, Australia does have the among the highest wages in the world especially for semi to unskilled work (though the average grad salary in SIN after 5 years of work, post tax is probably better than Australia)
I think the SIN cabin crew base operate almost like casual crew. The base pay is S$1000 then they only earn when they fly. If they don't fly they don't earn. And seeing as SQ cabin crew can earn very good money, and they are the benchmark, I don't think Tiger and Jetstar can greatly undercut SQ's cabin crew wages by all that much.