Allocasuarina torulosa is slender, usually dioecious tree that typically grows to a height of . Its branchlets are drooping, up to  long, the leaves reduced to erect, scale-like teeth  long, arranged in whorls of four or five around the branchlets. The sections of branchlet between the leaf whorls are  long,  wide and more or less square in cross-section when young.
Allocasuarina torulosa is a slender tree that can be either male or female, typically reaching a height of . Its branchlets hang down, up to  long, with leaves reduced to erect, scale-like teeth  long, arranged in clusters of four or five around the branchlets. The sections between leaf clusters are  long,  wide and more or less square in cross-section when young.