Hundreds of police are preparing to storm a coal seam-gas protest camp following weeks of mounting tension in northern NSW.

Up to 800 police will enter the camp at Bentley, near Lismore, as early as Monday to disperse thousands of people who have been protesting for several weeks.

Police Association president Scott Weber has warned that local stations could be left short-staffed by the large-scale operation, which will draw officers from across the state.

The raid, codenamed Operation Stapler, has been weeks in the planning and involved high-level discussions within the force. It is understood senior police have been reluctant to go ahead with the aggressive strategy, fearing it is a lose-lose situation.

Monday signifies the first day of Metgasco's gas drilling operation, with a rig set to drive onto a farmer's private property at Bentley.