Acacia genistifolia and Acacia ulicifolia are very similar. To tell the difference, you need excellent photos of the leaves and their attachment to the stem, showing whether there are fine stipules (outgrowths) between the bases of the leaves and the stems or not.
The shape of the leaves is A. genistifolia. The natural variability of plants and the various descriptions and keys can make it difficult. In this instance I looked at Acacias of Southeast Australia by Terry Tame. Acacia genistifolia phyllodes linear, terete to tetragonous. 12-35 mm long, 1-2 mm (-3mm) wide; rigid and mostly straight; apex abruptly contracted into a pungent point; base slightly swollen … while Acacia ulicifolia phyllodes crowded, usually more than 5 per cm; subulate and tapering from the base to the apex +/- tetragonous to +/- flat, 8-14 mm long, 0.6-1.6 mm wide; straight; base slightly dilated; apex acute and pungent … stipules long and thin. For the plants I have seen in this area it is the shape of the phyllodes (wide base for A. ulicifolia) that is a distinguishing feature. There could be similarity with A, siculiformis with phyllodes narrow elliptic, flat, 10-30 mm long, 1.5-4 mm wide; straight to curved; rigid; apex acute with pungent point; mid-nerve prominent … gland small, near the centre of the phyllode. (I'm not familiar with this one).