But Alan Hayes, the staunch campaigner against South Korean proposals to mine under sensitive Wyong water catchment areas, is quietly optimistic that the renewed Kores application for its Wallarah 2 coal mine is doomed to fail.

"There have been suggestions from the Opposition that the NSW Premier Barry O'Farrell has reneged on his pre-election promises to stop this project but I have to say that really all he has done is to accept that Kores are legally entitled to waste their money with another application and that he has a legal obligation for it to be duly considered," Mr Hayes said on Monday.

"But I have no doubt that the Kores application will fail on the same grounds that it failed before. At stake is the water supply to 300,000 Central Coast people and we have solid proof that mining will seriously endanger that supply if not actually destroy it," he said.

Mr Hayes said that pre-election promises to protect the area from mining made by Premier O'Farrell and Energy and Resources Minister Chris Hartcher were more than just promises.

"It is a formal commitment in writing with their signatures, and also a formally declared Liberal Party policy," he said.

Mr Hayes said a state government insider had recently told him that the mine would not go ahead. The insider reportedly said Kores's exploration licence runs out in December and such was the significance of protecting the water catchment that the licence would not be renewed.

But the hardened campaigner said his Australian Coal Alliance (ACA) was nevertheless prepared to fight in the event of a government backflip.

"We are now an experienced and very well-resourced group of residents and if need be a media holocaust will follow any suggestion by its action or non-action that this government was elected on a lie," Mr Hayes said.

"In the meantime the ACA and O'Farrell government are allies with common goals."