The meeting, convened by the NSW Planning Assessment Commission, came on the heels of a 3000-strong rally against coal seam gas mining on the Sea Cliff Bridge near Clifton on Sunday.

Northern Illawarra Sustainability Alliance spokesman Peter Turner, who was at the meeting, feared the bore hole would pave the way for mining inside Sydney Catchment Authority’s special areas if it was approved.

‘‘So far Apex have 15 approved exploration bores, 10 of which are on special areas land. If the new bore gets approved, that would be an implicit approval for a commercial gas field across an area set aside by Parliament in 1998 to protect our water,’’ Mr Turner said.

Retired geosciences academic Ann Young, who was at the meeting, completed her PhD on the upland swamps of the Woronora plateau and is worried about coal seam gas mining’s impact on Sydney’s water system.

‘‘My concern about coal seam gas mining is that development of a mine would mean wells spaced 300-600 metres apart and this and the associated access tracks would be a huge impact on the water catchments,’’ Dr Young said.

The Leader was unable to contact Apex Energy for comment before going to press, but a statement on the company’s website contests environmentalists’ claims drilling would compromise Sydney’s water system.

The statement said there were no significant aquifers in the Apex area and more than 150 bore holes existed in the Sydney catchment areas of the Woronora plateau.

‘‘Most of these have been drilled by the Sydney Catchment Authority itself for exploratory reasons,’’ the statement said.

‘‘There is already a significant record of safe drilling in the Sydney catchment areas.’’

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