Sydney Knitting Nannas and Friends and Water for Rivers rallied on July 15 to call on the Independent Planning Commission (IPC) rule against Santos' Narrabri Gas Project.
Santos wants to set up 850 coal seam gas wells in the Pilliga Forest, a recharge area for the Great Artesian Basin.
It is currently before the IPC. More than 400 people have registered to speak at its public hearings, originally set down from July 20-24, but which now includes two extra days.
The protest began outside the IPC, where protest songs were sang, and then marched to the CBD, along Pitt Street mall, and ended at the back of NSW Parliament.