Grave concern is swelling across NSW about the rapid expansion of CSG exploration.

"We don't want them doing to our land what they've done in Queensland," Markwell landholder Dave Saul said.

"They've left nothing but devastation and heartache and we're not going to let it happen here."

Guest speaker Drew Hutton, president of the Lock the Gate Alliance, sent a strong message to the audience.

"I can't tell you how to win, but I can tell you how to lose - by negotiating with them," he said.

"The mining industry has been negotiating for 50 years. If you start to negotiate, then you're starting to lose."

A question and answer session was well utilised by locals, raising a number of concerns ranging from farming bio securities and land subsidence issues to the impact on the Myall lakes - registered under the international RAMSAR wetland convention.

"We just can't risk it," Myall River local landholder Charlie Shuetrim said.

"The use of toxic chemicals near such a fragile ecosystem is just criminal. The effects of some of these chemicals on soil and groundwater aren't even known yet. It's just not worth it, we've way too much to lose."

A motion was passed almost unanimously to form an action group and join the 100 odd communities of the Lock the Gate Alliance.

The first meeting for the group will be held this Thursday, August 25 at 7.30pm in the Bulahdelah School of Arts Hall.