Farmers opposed to Santos’s coal seam operations in north-western NSW have begun legal action to force the company to reveal information about alleged contamination of two water bores near exploration wells.

The Mullaley Gas and Pipeline Association applied to the NSW Land and Environment Court on Wednesday to require Santos to release water-monitoring data related to drilling near one farmer’s property south of Narrabri. The NSW Environmental Defenders Office is representing the group.

Tony Pickard near a CSG well.

The grazier, Tony Pickard, had previously made public concerns that two of his bores had begun producing undrinkable water in 2012, forcing him to install rainwater tanks. The bores are located one or two kilometres from seven active CSG wells, known as the Dewhurst 8 pilot site, on the neighbouring property.

"We believe there is a case that CSG activity has caused this groundwater pollution incident, however we are missing a few vital pieces of information,” said David Quince, a farmer on the Liverpool plains and chairman of the association. "We have been driven to this action as a result of the secrecy employed by Santos and the disinterest shown by the NSW government. We are acting now out of our deep concern for the future of groundwater in our region and the major risks posed to it by CSG drilling.”