Waiuku is a rural town in the Auckland Region in the North Island of New Zealand. It is located at the southern end of the Waiuku River, which is an estuarial arm of the Manukau Harbour, and lies on the isthmus of the Āwhitu Peninsula, which extends to the northeast. It is 40 kilometres southwest of Auckland city centre, and 12 kilometres north of the mouth of the Waikato River. The town serves to support local farming, and is the residence of many employees of New Zealand Steel at Glenbrook, which is four kilometres to the northeast.