Kaisun Holdings announced it had entered a memorandum of understanding for the joint development of "two 1000-megawatt ultra super critical" coal-fired power plants in the Hunter Economic Zone. 

At that size, it would more than replace AGL's ailing Liddell power plant, with its 1680MW-capacity, that is due to close in 2022.

The Nature Conservation Council (NCC) has called on all state parties to block the proposal. 

“The way Ms Berejiklian and Mr Daley respond to this latest threat will be a test of their commitment to a forward-looking climate and energy policy," NCC chief executive Kate Smolski said. 

The Newcastle Herald understands Cessnock City Council's mayor and general manager have been briefed on the plan. 

Kaisun, which is incorporated in the Cayman Islands, said it had entered into "strategic cooperation framework" with China Energy Engineering Group - one of the country's biggest power plant developers.

The two would work with Cavcorp, a Parramatta-registered company with $25,002 in paid up shares that is the "initiator for the project", and which has plans to the develop the HEZ site near Kurri Kurri.

Cessnock mayor Bob Pynsent said Francesco Cavasinni, who Cr Pynsent said owns the HEZ site, had briefed the council a few weeks ago on the "left-field" plan.

According to ASIC records, Mr Cavasinni is the only current shareholder of Cavcorp Australia and is both director and secretary of the company dubbed "initiator for the project", which has $25,002 in paid-up shares. 

A Planning spokesman, however, said "there had been no formal application and no meetings with department officials".

Cr Pynsent said the state would decide the plan's future.

A NSW Planning spokesman said there had been no formal application to date and no meetings with officials. ​

A spokesman for federal energy minister Angus Taylor said the Morrison government was aware of the reports but said it was "not involved in this MOU". 

Greens energy spokesman Adam Bandt said the party would fight "tooth and nail" to prevent the plan. 

“We’ve just had the hottest summer on record," he said. "We need to close down coal-fired power stations, not build new ones."

The 850-hectare Hunter Economic Zone had been planned to offer a shot in the arm to Kurri Kurri. 

Instead, council plans to approve a development at the site were overruled in the Land and Environment Court in 2016 due to the presence of the endangered regent honeyeater. 

"The background is that the HEZ has a history of environmental issues and they would have to be sorted before it could go ahead," Cr Pynsent said.