The forum follows the first public meeting held in Cobbitty on June 14.

More than 60 concerned residents and AGL employees packed the community hall to hear speakers including AGL Group general manager for upstream gas Mike Moraza, Greens upper house MP Jeremy Buckingham, Macquarie Fields MP Andrew McDonald, Helen Redmond from Doctors for the Environment and Jacqui Kirkby from the Scenic Hills Association.

Residents voiced concerns about the proposed expansion of the Camden Gas Project into parts of Campbelltown, including the Scenic Hills, during the two-hour meeting.

The plans, which propose 12 gas well sites over an area of 38 square kilometres, are currently before the state government.

Mr Moraza said the Camden Gas Project supplied up to 6 per cent of the state's natural gas.

He defended the company's use of drilling techniques, hydraulic fracturing and water and chemical use.

Both Dr Redmond and Mr Buckingham expressed concern about coal seam gas mining and advocated for a moratorium on the practice until it had been investigated further.

Scenic Hills Association spokeswoman Jacqui Kirkby told the forum mining was incompatible with land use in the Scenic Hills.