In a statement, police said the two women, aged 24 and 39, were with a larger group that was canyoning in the area when they were sucked into the water. The women have not been seen since.
The other members of the group were not injured and were assisted by police, paramedics and other emergency services personnel at the scene.
The incident followed rainfall in the area. Previous canyoning tragedies caused by suddenly rising waters have prompted warnings about the dangers of the activity.
Canyoning involves people dropping into a watercourse at the bottom of a narrow gorge and travelling with the flow to an exit point.
Signs at popular canyoning spots in NSW warn people to avoid the activity if rain is forecast or if the weather appears changeable. Even experienced canyoners are at extreme risk in the event of flash flooding.
