I'd say it was an odd-ball Straw-necked Ibis (Threskiornis spinicollis): juvenile with leucism. The head is still feathered, so it's a juvenile. Possibly a cross with a Th. molucca? Whatever, it's unusual.

Panicles ascending to c. 45 cm high. Note the stout rhizome, absence of a defined tussock, the spreading panicle (like a diminutive Rytidosperma pallidum panicle), scarlet anthers, long palea and short lemma lobes.

Abundant but I saw only two flowering plants out of dozens of patches of the species. One of the two was burnt a few years ago; the other not for decades.

This species is very shy to flower except in the summer following a fire, which perhaps explains why it hasn't previously been recorded anywhere in southwest Victoria. It may be flowering this season due to the abnormally high, consistent rainfall over recent months.

My thanks to Lauren Kivisalu, who found a flowering plant of the species at this site and drew my attention to it by asking what it was.