The department of planning has also sought to clarify its role in the approval process of the Warkworth mine extension, which is needed to maintain economies of scale at the mine at a time of lower coal prices.

The Minister for Planning Brad Hazzard is joining the company in appealing the Land and Environment court decision.

“The Warkworth extension was initially approved by the independent Planning Assessment Commission – not the Minister for Planning and Infrastructure,” it said.

“The NSW government has reduced ministerial discretion in planning matters – starting with the scrapping of the Part 3A regime.

“In the two years since coming to office, the Minister for Planning and Infrastructure Brad Hazzard has not approved a single private development – which includes any mines.”

The new planning system proposed by the current government, which was devised to stop ministers having undue influence over mine approval planning decision, has not yet gone to parliament.

“Contrary to the claims, the new planning system maintains the existing processes allowing objector merit appeals against high-impact projects,” the department said.

The NSW government planning process has been criticised for creating investor uncertainty because developments such as the Warkworth extension had passed through all relevant state and federal approvals before being challenged in the NSW Land and Environment Court.

The old planning system had also allowed the former Minister for Mines Ian Macdonald to allegedly ignore departmental advice and approve the exploration lease for the Mt Penny mine for his political ally Eddie Obeid.