The Environment Protection Authority report found one in 10 of the well heads in the Camden gasfield were leaking methane gas, despite an earlier 10-day investigation by AGL giving the field a clean bill of health.

The leaks, and the EPA and AGL's failure to release the information until it was sought under freedom of information laws, have been greeted with outrage by local anti-coal seam gas activists.

"This I find astounding: that AGL expects us to live in their gas field but they do not want us to know what risks or fugitive emissions we are expected to live with," Michael Streatfeild, secretary of Stop CSG Macarthur, said.

"The EPA I assumed was there to protect the public, so once they have received the report, why don't they make it publicly accessible?"

AGL's first leak detection report on the project, which was posted online only after local opponents sought access to it under freedom of information laws, shows the EPA found nine of its 95 CSG wells to be leaking when inspected late last year.

Two of the leaks were deemed to be "significant", with methane emission readings in excess of 50,000 parts per million.

The EPA findings, made from September to December last year, came just months after AGL's own audit of 120 well heads during 10 days in late April last year found no leakages.

"Does it mean that there's no ongoing monitoring, or just spasmodic efforts?" Mr Streatfeild said, adding he was advised by the EPA to seek the report under GIPA provisions after the company refused to release it.

The EPA said that the difference between its findings and AGL's was "because the monitoring periods are different".

"None of the leaks in the AGL report constituted as a breach of [AGL's] Environment Protection Licence," the EPA spokeswoman said.

According to a CSIRO report for the NSW Chief Scientist released last year, odourless methane poses two potential hazards: as an asphyxiant displacing oxygen needed to breath, and being flammable at sufficient concentrations.

There is no indication that methane leaks from the wells and other facilities reached any where near hazardous levels.

"Following the EPA's inspection, corrective action was taken by AGL to repair the leaks," a spokeswoman for AGL said.

"This included the tightening and replacement of fittings, well heads and valves where appropriate," she said, adding that AGL conducted further testing to ensure the corrective actions were effective. 

One "significant" leak required only the tightening of studs to fix, while the other took a day, according to the report.

Chris Patterson, the Liberal state member for Camden, said the government had heeded residents' concerns about the project and had "completely hit on the head" AGL's expansion plans.

Mr Patterson also said annual leakage reports, required since last year, should automatically be made public by the EPA: "The industry should be open and transparent to ensure the correct information out there... [to] allay fears."

Mr Patterson was visited by about a dozen CSG opponents at his Camden office on Friday.

"Residents wanted to know why the NSW government's 2 kilometre buffer zone for CSG in residential areas [in place since last year] does not apply to the thousands of residents living in the Camden electorate right now," said Dan Robins, western Sydney co-ordinator for Lock The Gate Alliance.

Greens coal seam gas spokesperson Jeremy Buckingham said AGL had been "a serial offender with multiple breaches at their Camden facility".

"It is disturbing that the EPA detected leaks that AGL failed to detect, which brings into question AGL's ability to regulate itself or be honest about their operations," Mr Buckingham said.

"AGL are currently blocking the release of EPA audits of their coal seam gas operations at Broke and Gloucester, raising the question: what else do they have to hide?"

smh.com.au