http://www.tourism.australia.com/doc...3_SING-Web.pdf
In 2012 there were 343,000 visitors from Singapore to Australia. I think in 2013 it grew another 10%, so 377,000
SIA had a 50% marketshare of Singaporeans (note this only refers to Singaporeans travelling from Singapore to Australia, not other nationalities ) to Australia (despite the outrageous fares ex SIN). QF had 16% and Scoot 14%.
In 2008, SIA had a 64% marketshare and Qantas 24%. In 2012, SIA had 50%, Qantas 16% and Scoot 14%. And this is before QF cut capacity to SIN.
I would be very interested in what the 2013 Tourism Australia report on Singaporean visitors shows. (Another interesting note: Without Scoot, SIA had a 64% market share. With Scoot, SIA has 50% and Scoot 14%. Does this mean that SIA's pax just defected to the lower yielding Scoot, and would have flown SQ if Scoot didn't exist?)
In 2013, about 1 million Australians visited Singapore (that is, they cleared immigration) So daily O&D demand between Singapore and Australia is around 3700. It's not exactly insignificant, enough to fill 13 fully loaded A330s.