What you're describing is smaller parties benefiting from PV. You haven't addressed your claim. Labor is the big party and the smaller conservative parties are benefiting.
In the Australian context, the big parties are Labor and the Coalition. The Coalition is formally an alliance of two parties, but in many situations they act like a single one–indeed, in Queensland they actually merged into one (the LNP), and effectively they are a merged party in the NT as well (the CLP), although that technically was never a "merger" as such. The Nationalists and Country party in 1918 were the historical predecessors of the current Coalition. The "small parties" are the minor parties which are neither Labor nor the Coalition, but still manage to win some seats in Parliament–nowadays primarily the Greens on the left, One Nation on the right, and a random mishmash in the middle–although as we go back through the decades, other players have risen to prominence only to subsequently fade away (most notably the Democrats and before that the DLP). And then you have the "micro parties" which run candidates but never win any seats, or one or two of them might strike it lucky on very rare occasions (like the now-defunct Motoring Enthusiasts Party did in 2013).