New coal mining proposed for NSW's Hunter region must be stopped because there isn't enough rail or port capacity or global demand to shift it, a report backed by Malcolm Turnbull warns.
"We want it to decline," the former prime minister said on Wednesday.
"If it doesn't decline, we're going to keep burning coal and we'll never reach our greenhouse gas emission reduction goals globally, let alone nationally."
Proposals for new coal projects have a combined output of almost 100 million tonnes per year or 10 new Adani-sized mines in the Upper Hunter Valley alone, according to the Australia Institute.
Now head of the NSW Net Zero Emissions and Clean Economy Board, Mr Turnbull says a comprehensive plan and moratorium needs to replace the focus on transient royalties.
However, Resources Minister Keith Pitt said the Australia Institute was better known as "an activist organisation promoting Labor's left fringe ideology".
"Coal mining will remain a major industry for Australia, including the Hunter, for decades to come," he told AAP.
"It is generating the energy in many developing nations to provide the essential services and economic opportunities that help lift people out of poverty."
As well as coal, NSW has a net zero emissions by 2050 policy that is matched, or bettered, by all of Australia's states and territories.
Prime Minister Scott Morrison has said Australia should get to net zero emissions "as soon as possible", perhaps by 2050, but is yet to make that a federal policy.
Mr Turnbull - who owns land in the Hunter - said when mining companies failed to meet their rehabilitation obligations, it was the community and state government that picked up the tab.
"You could have billions and billions of dollars in liabilities," he said.
Australia Institute chief economist Richard Denniss said existing coal mines were already operating well below their approved capacity.
"Trying to build 10 new Adani mines' worth of coal mines in the Upper Hunter at precisely the time world demand for coal is falling is absurd," he said.
The report warns against approving "zombie" coal projects that won't be built as no one wants to invest next door to a mine site.
"We are not going to be coal mining in the Hunter in 30 years' time. They're seeking to get mines, get in before the party ends," Mr Turnbull said.
He said there was already enough capacity in the Hunter for coal mines to meet existing export demand and not damage the local thoroughbred industry.
Unlike coal, it could still exist in 100 or 500 years, he said.
The coal industry is currently proposing 23 new coal mines and mine extensions across NSW with a combined additional annual production of more than 155 million tonnes.
These proposals follow the doubling of production from 130 million tonnes in 2000 to 260 million tonnes in 2014, the report found.
Australian Associated Press