The NSW Environment Protection Authority has been "captured by industry" and starved of the resources needed to do its job, according to submissions to an inquiry into the agency.

An upper house inquiry into the EPA's performance is examining its overall activities but also how it handled six cases. These include land contamination at Botany and Hillsdale, its investigation into the effects of coal dust pollution in the Hunter and ground water contamination by Santos at its coal-seam gas exploration in the Pilliga.

Narrabri grazier Tony Pickard has reported suspected contamination of water by Santos.

In its submission, the Nature Conservation Council said a general view among its 130 member groups was that the EPA was an ineffective regulator that had lost the trust of the community.

Having an EPA is "critical" for protecting the environment "but it needs to be independent and it needs to be resourced", Kate Smolski, the council's chief executive, said. "It's too close to industry and puts industry ahead of the public."