I am inclined to think this is Pimelea linifolia rather than Pimelea ligustrina subsp. ligustrina. The edges of the inner bracts in Pimelea linifolia are hairless, while those of Pimelea ligustrina are ciliate (with short hairs). Pimelea linifolia occurs at much lower altitudes than Pimelea ligustrina. "Outside Canberra Nature Park" gives no indication of what the altitude was.
Thanks Betty - this record is from the lower slopes of Mt Jerrabomberra probably around 650m so that fits with your inclination that this is P. linifolia