Green’s Dictionary of Slang

riverina n.

[rhy. sl. = deana/deaner n.]

(Aus.) one shilling.

[Aus]Baker Popular Dict. Aus. Sl. (2nd edn).
[Aus]N. Pulliam I Travelled a Lonely Land (1957) 238/1: riverina – a shilling.
[UK]Dodson & Saczek Dict. of Cockney Rhy. Sl.
[UK]R. Puxley Cockney Rabbit.