On Friday a department spokesman said the independent Planning Assessment Commission's approval of the DZP included a finding that the "waste in its existing form does not qualify as radioactive".

The senator visited Dubbo this week where she told of a rare earths mine in Western Australia and others in China.

"So there is already considerable rare earths material in the marketplace," she said.

"We're not opposing the mine (DZP), but there's a question mark over the need for this mine considering the complexity of a mine where uranium will end up as part of the waste products."

The department spokesman said a stringent waste management plan was in place as a condition of the mine's approval.

"The department's compliance team will closely monitor the mine to ensure it meets the conditions of its approval," he said.

"The proposal was rigorously assessed against strong environmental and safety standards."

The spokesman also addressed the need for the mine, at least in the Dubbo region.

"The independent Planning Assessment Commission found that the project would have significant social and economic benefits in the form of investment and employment for the Dubbo region," he said.

Ms Rhiannon attended a Friends of the Earth information night on the DZP on Tuesday night at Dubbo.

On Wednesday morning she was "happy" to show support for the organisation's Radioactive Exposure Tour as it prepared to leave Dubbo's Macquarie Street for Broken Hill.

Later that morning she visited the office of the Daily Liberal in the company of the Greens' candidate for the seat of Dubbo at this year's state election, Matt Parmeter.

Ms Rhiannon told this newspaper that at Tuesday night's meeting Alkane Resources general manager NSW Mike Sutherland had emphasised that the DZP would operate under a "whole number of conditions".

"However the mining industry in NSW has very poor credibility because it's been notorious for not abiding by the conditions imposed on them," she said.

"It rarely is fined when it breaks those conditions and the fines are very low."

The senator accused mining companies of becoming "quite expert at talking to the public but not disclosing the real workings".

"Many of the issues we're talking about with regard to health and safety, environmental protections and standards for workers are issues that mining companies see will cut their profits, so what they often do is cut corners," she said.

"So they're not addressing those issues properly, and that's why the Greens think that this project is under a cloud."

Asked if she had read the approval conditions for the DZP, Ms Rhiannon said: " Not in detail. I've read the interviews about it and I've read summaries of it but I haven't read the whole EIS (Environmental Impact Statement)."

Ms Rhiannon's statements prompted comment from the NSW Minerals Council, the leading industry association representing the state's minerals industry.

"Senator Rhiannon's comments are as ill-informed as they are ridiculous," said its chief executive officer Stephen Galilee.

" It's what we've come to expect from a Sydney-based senator whose stated view is to shut down mining in NSW within five years."