The legalities around a pump sucker of any sort are tricky/hard to interpret because - hand operated or not, they use "water" to lift gravels or pay dirt.
Using water to lift something is classed as hydraulic. Hydraulicly excavating (removing paydirt(what a sucker pump does) from creeks & crevices) is not allowed & works on the same principals as a dredge operates.
Might be getting into the nitty gritty of it all, but if you really look into it I would say it is not allowed.
But...
I on the other hand, have one(small sucker pump) & use it & won't be hiding it if I get questioned.
If you use is descretely & it's only a small sucker, I don't think any ranger will raise an eye brow.
I use an oil transfer pump - (small version of a yabby pump) about 30cm long, it's ready to go from the shop - sucker hose & all.
About $18 from SuperCheap Autos.
Friends of mine have been aproached in the past whist prospecting & the ranger only seemed interested if they were getting any colour. He wasn't interested in their highbanker or the pump they had to run it.