Catchment authority officials have made numerous recommendations and remain confident no pollution of the water supply will occur if they are adhered to.

A Sydney Catchment Authority spokeswoman said the proposed Apex Energy coal seam gas exploration bore located in the Warragamba catchment was on private land at Oakdale, about 20 kilometres away from Warragamba Dam.

Drilling of the borehole was approved in June this year.

"The Sydney Catchment Authority provided comments on the company's review of environmental factors and made a number of recommendations," she said.

Recommendations included the preparation of a water management plan, an erosion and sediment control plan, rehabilitation of the site, an emergency response plan and notification of any incidents.

The Sydney Catchment Authority had also recommended that if the project was approved, the conditions should specify no fracking.

"Apex Energy has addressed these recommendations," the spokeswoman said.

The controversial fracking technique involves pumping water, sand and chemicals underground to fracture the rock walls and force coal seam gas to the surface.

The effects of rock-dissolving chemicals on underground water tables is what some people are concerned about.

On their website, Apex Energy states: "Our position is clear, we have no intention to complete any wells via the fracking completion method.

"APEX is currently considering other innovative ways which do not involve fracking to successfully deliver gas."

Coal seam gas activities are regulated by the Department of Trade and Investment, Regional Infrastructure and Services and the Department of Planning and Infrastructure.

The Sydney Catchment Authority provides expert advice before consent is granted.