It follows a Lock the Gate analysis of the annual reviews of four mines - Muswellbrook, Bengalla, Mt Pleasant and Mt Arthur - that found the overall area of active disturbance was 2.3 times the area of land under active rehabilitation. The average area of active rehabilitation as a percentage of the total footprint was 27.5 per cent.

The most recent independent environmental audits for the four mines describe rehabilitation efforts compromised by inadequate human resources and systems. Poor results from drone seeding, erosion and weed infestation were cited as evidence of a lack of personnel dedicated to rehabilitation management.

A NSW Minerals Council spokesman said all mines were required to meet strict rehabilitation obligations as set out in their conditions of approval and work to ensure disturbed land was progressively rehabilitated throughout the mining lifecycle.

"The regulator regularly monitors rehabilitation progress and mines are required to report annually," he said.

Mt Arthur and Mt Pleasant mines did not comment on the analysis.

A spokesman for Idemitsu Australia Resources, which owns Muswellbrook Coal, said the company regularly reviewed its rehabilitation plan to assess its progress and to ensure its environmental consent obligations can be enhanced and achieved.

"We are fully committed to achieving our approved rehabilitation plan and confirm that the Muswellbrook operation is currently in compliance with its regulatory obligations," he said.

New Hope, which owns the Bengalla mine, said site management worked closely with government regulators to ensure annual rehabilitation obligations were met.

"We provide an annual public report on the progress of rehabilitation on our sites and welcome any well-informed scrutiny that follows," he said.