20 Marks Australian occupation, treasury note

When Australian naval forces seized German New Guinea in September 1914, they inherited a functioning colonial economy with no suitable currency to run it. The Rabaul treasury notes — printed locally under occupation administration rather than shipped from Australia — were an improvised fix, produced with whatever materials and equipment were at hand in the captured town. The series is among the very few instances of an occupying power issuing emergency currency from the occupied territory's own printing infrastructure.

Three denominations were produced. All are genuinely rare; the 20 Mark value more so than the lower figures.