Upper Hunter candidate Tony Lonergan admits he's gratified by the effort the group is putting in to convince the electorate not to vote for him.

He said the fact the NSW Minerals Council had letterboxed households in the region, scaremongering that the Greens were after people's jobs, proved his point.

"Nothing could be further from the truth," Mr Lonergan said.

"The Greens stand for a healthy and diverse future for the Upper Hunter.

"We know the coal industry is on the way out and have announced a $1.8 billion transition fund to assist workers in the coal and power industry to move into more sustainable jobs."

But, NSW Minerals Council CEO Stephen Galilee backed their campaign 100 per cent.

"We stand by our efforts to highlight how the policies of the NSW Greens to shut down the coal sector in 10 years would cost thousands of mining jobs," he said.

"Communities like Muswellbrook and Singleton would be among the worst affected."

Mr Lonergan said the multinational coal companies, who made up the NSW Minerals Council, were threatening miners' job security, pay and conditions more than the Greens.

"Rio Tinto has pulled out of thermal coal, Glencore's put a cap on production, the Chinese market is unpredictable and the world is moving away from high carbon emissions," he explained.

"The writing is on the wall for coal and it is time for the Upper Hunter to move on.

"The Greens are interested in the future of the Upper Hunter and an orderly transition into other jobs and a diverse economy.

"The multinational coal companies are only interested in themselves.

"Their letterboxing campaign against the Greens is a sign of desperation.

"The NSW Minerals Council's leaflet contains information likening the coal industry to the tobacco and asbestos industries that have killed thousands of people in Australia.

"Emissions from the Upper Hunter power stations are life-threatening.

"The sooner we move to cleaner renewable energy sources the better."