Construction of a coal seam gas (CSG) waste water treatment plant in north-western New South Wales will continue for the time being after a court case challenging its approval was adjourned in Sydney.

Key points: Santos wants to build CSG waste water treatment plant near Narrabri

Santos wants to build CSG waste water treatment plant near Narrabri Opponents say environmental impacts not properly considered

Opponents say environmental impacts not properly considered Santos says ample comment opportunity given, and process was "rigorous"

A group calling for greater scrutiny of the Santos plant at the Pilliga State Forest near Narrabri was set to tell the Land and Environment court it had serious concerns about the approvals process and potential environmental impacts of the facility.

The legal action was launched by the Environmental Defenders Officer (EDO) on behalf of a community group, People for the Plains.

The group argues a more robust assessment process should have been used for the NSW Government's approval last year of the facility.

But legal teams for all parties, including those working on behalf of the NSW Government, outlined that further consideration was needed for new information and summons.

Santos, which has received approval to build the facility on a property it co-owns, wants to store, process and treat waste water from its coal seam gas wells in the area.

Speaking ahead of the hearing, People for the Plains group spokeswoman Sally Hunter said there should have been more opportunity for public feedback.

"The Review of Environmental Factors (REF) process was a fairly brief process and we were not really allowed to comment," she said.

"There was not really a proper consultation phase."

There are already storage ponds on site but the company hopes the new Leewood facility will open the way to treat 500 megalitres of toxic waste liquid water for irrigation.

Santos maintains the approvals process has been correct and proper.

Mine approved after 'rigorous and detailed assessment process'

But People for the Plains told the ABC it had concerns around using the treated waste water in that way.

"We find that very concerning because of the salts that can't be removed through that plant," Ms Hunter said.

"There is also still a question as to what happens to those salts once they've been crystallised, and where they'll be disposed of, how safe that will be.

"Because they're highly toxic salts that aren't supposed to be in the environment."

A Santos team including Santos General Manager Energy NSW Peter Mitchley (right) at a CSG pilot well near Narrabri.

Santos said there had already been a proper stage of community consultation for the development.

"The REF was placed on public exhibition and both the EDO and People for the Plains lodged submissions on it before the activity was approved", Santos's General Manager of Energy NSW, Peter Mitchley, said in a statement.

Last year, the ABC obtained documents showing serious concerns raised by the NSW Government after the REF was published.

Mr Mitchley said the mine had been approved following a "rigorous and detailed assessment process" and was of low environmental risk.

The case will resume on May 17.