* Oil and gas giant Santos wants to build a $3.6 billion gas field over 95,000 hectares in the Pilliga forest and nearby grazing land in northwest NSW.

* It involves drilling 850 new gas wells over 20 years.

* Santos says it has the potential to provide up to half of NSW's natural gas needs.

* The gas will be made available to the NSW market via a not-yet approved pipeline linking into the existing Moomba to Sydney pipeline.

WHAT DID THE INDEPENDENT PLANNING COMMISSION DECIDE?

* Granted a phased approval subject to 134 conditions.

* Santos must meet specific requirements before it can progress to the next phase.

* This includes improving groundwater impact modelling, offsetting predicted greenhouse gas emissions and strengthening measures to mitigate impacts on flora and fauna.

WHAT DO PEOPLE THINK ABOUT IT?

"It's put a big dent in my trust in the process. I have been fighting this project for years, and truthfully, today, I was hoping for a rest. So now, the fight goes on," Narrabri farmer Stuart Murray.

"With 850 gas wells planned, along with more roads and pipelines, the Pilliga forest is going to be absolutely decimated," NSW Greens MP Cate Faehrmann.

"The fact that this project has been approved in 2020, in the face of a climate and extinction crisis, shows that our planning system is broken," NSW Independent MP Justin Field.

"Approving this project and developing new gas is fundamentally at odds with protecting Australians from climate change. It is sending us backwards," climate expert Professor Will Steffen.

"Santos now has the green light to desecrate the Pilliga forest - turning it into an industrial gas field that will damage groundwater, carve up the forest and endanger koalas and other threatened species," Nature Conservation Council of NSW campaigns director Dr Brad Smith.

"The commission's decision confirms that Narrabri gas is in the public interest and will provide new economic and job opportunities, particularly in the regions," federal Resources Minister Keith Pitt.

"NSW should be a thriving global heavy manufacturing hub, and that's exactly what we can become if we better harness our gas wealth. This approval is an excellent step," Australian Workers' Union national secretary Daniel Walton.

"The IPC outcome confirms that we have relied upon the best science to ensure the Narrabri Gas Project can be delivered safely and sustainably," Santos managing director and chief executive Kevin Gallagher.

Australian Associated Press