Green’s Dictionary of Slang

(Aus.) a rissole, esp. as cooked for shearers.

1965		J.S. Gunn Terminology of Shearing Industry ii 26: Speed balls, breakfast mincemeat rolls which are reputed (no doubt by the cook) to make shearers faster. The explanation may be in the effect on the shearers’ bowels [AND].
1978		J. Dingwall Sun. Too Far Away 40: ‘Bloody good cook.’ [...] ‘Speed balls. That was his specialty.’ [...] ‘Rissoles.’.
1979		K. Garvey Absolutely Aus. 18: The cook with his speed-balls delightful, / The learner attempting to shear, / The rouseabouts lazy and spiteful, / The presser with yoke in his hair.