It's the stretch of beach between Main Beach and Surfers Paradise.
www.google.com:443/maps?q=narrowneck+gold+coast,+qld,+australia&hl=en&ll=-27.981403,153.433385&spn=0.025089,0.039697&sll=37.0625,-95.677068&sspn=47.435825,81.298828&vpsrc=6&hq=narrowneck&hnear=Gold+Coast,+Queensland,+Australia&t=h&z=15
Used to be a very popular spot, before my time.