The ICAC is examining particular aspects of lobbying activities and the corruption risks involved in the lobbying of public authorities and officials.

Decisions about mining projects are predominantly made in Sydney, agencies that contribute to those decisions are based in Sydney and politicians that hold sway over such decisions meet and debate in Sydney, Lock the Gate NSW coordinator Georgina Woods told the ICAC.

On Monday ICAC's 'Operation Eclipse' heard evidence specifically about the mining industry.

NSW Minerals Council chief executive Stephen Galilee also gave evidence.

The hearing comes just two days after Planning Minister Rob Stokes announced a review of the Independent Planning Commission's role.

The IPC last month refused an application by South Korea's KEPCO for a coal mine development in the Bylong Valley, sparking outrage from the NSW Minerals Council.

IPC chairwoman Mary O'Kane is scheduled to appear Tuesday.

Mr Stokes' review of the IPC's role comes after four weeks of advertising and media pressure by the NSW Minerals Council following the IPC's decision to refuse approval to a coal mine on strategic agricultural land in the Bylong Valley.

Ms Woods said, "The evidence we are giving the ICAC shows a pattern of undue negative influence being exerted over the NSW government by the mining industry, which is being repeated right now as the planning minister accedes to the coal lobby's demands to abolish the IPC or bring it to heel.

"The Minerals Council wants the IPC abolished precisely because it is independent," she said.

"It can't be lobbied. It's brief is to make decisions based on evidence and unlike the minister and the planning department, it operates transparently.

"The ICAC needs to bring sunlight to the clandestine influence the coal lobby is wielding over government in New South Wales," Ms Woods said.

You can see the ICAC livestream here.