The review, requested by the state government, brought together acknowledged experts in a range of relevant disciplines to examine the question of cumulative impacts on water quantity and quality.

They determined that though it was not possible to get a detailed understanding of cumulative impacts on water quantity, contemporary treatment processes were sufficient to protect the quality of Sydney's drinking water against any adverse impact.

"I have recommended the government create a whole-of-catchment data repository, and that will enable better modelling of the cumulative impacts of activities, such as CSG extraction and longwall mining," Professor O'Kane said.

The review found no evidence to suggest current activities in the catchment should be halted.

Prof O'Kane also recommended the state government strengthen industry insurance requirements to guard against possible environmental damage from CSG activities, and consider establishing an environmental rehabilitation fund to address unforeseen or long-term environmental impacts and remediation.

Stop CSG Illawarra spokeswoman Jess Moore said the report failed to rule on whether CSG mining was safe.

"This report cannot be used as the basis for green-lighting CSG development in our catchment," she said.

"It advocates that current activities proceed, making no comment on new activities.

"Communities have told this government time and time again that the risks of CSG mining are not OK in our catchment.

"Drinking water is off limits."

Prof O'Kane's independent review of CSG activities in NSW is ongoing.