The NSW Planning Assessment Commission has given approval for the reopening of a coal mine in a region of the Blue Mountains that it had previously deemed to be "incompatible with the significant conservation of the site".

The commission's determination supporting the extension of the Invincible Coal Mine also came despite its conclusion that the current state of rehabilitation on the site had been "suboptimal" and a requirement to fill three residual voids was "unlikely to be achieved".

The independent agency had previously rejected a mine proposal made by then owner Coalpac Corp that had been granted by the Labor government in 2008. In its 2014 report, the commission said open-cut mining intruding into the nearby towering sandstone pagodas in the Gardens of Stone posed "unacceptable risks and impacts, and only limited short-term benefits".