<<<Viscount west of Winton>>
It was this one, Ansett, 24 lost, 1966 :
http://aviation-safety.net/database/1966/660922-1.htm
But this reminds me of a slightly worse Viscount loss in Australia, MacRobertson Miller, 26 lost in 1968 :
http://aviation-safety.net/database/1968/681231-2.htm
The archives also show an even more severe loss of 29 to a TAA F-27 in 1960, which seems to be the worst Australian commercial airline crash :
http://aviation-safety.net/database/1960/600610-1.htm