and the government would be forced to call an election because they'd soon have no money. Either the Oppostion has to successfully pass a no-confidence motion in the Lower House, which could only succeed when there's a hung parliament, OR the Senate can block supply.
But if the Abbott government continues its downward slide, they may well reach the situation we had in 1975, where public opinion was overwhelmingly in favour of the Whitlam government resigning and calling an election because things were in such a shambles. But the people can't make the government resign. When Whitlam refused, that was the signal for Malcolm Fraser to refuse supply. Fraser was in the Upper House blocking supply and Whitlam in the Lower House presiding over repeated motions of confidence in the government. Total lunacy prevailed, but as we know, the G-G stepped in and sacked the government, taking the matter out of Whitlam's hands.
Just goes to show what a mess you get into when you do a deal to allow a media tycoon to dictate policy.