Owned by Peabody, Metropolitan Colliery has been under pressure after a series of pollution incidents last year.

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In August, the Environment Protection Authority fined the miner $15,000 after polluted water ran off into a creek that led to the Royal National Park.

The clean-up was continuing in October, with pollution extending into a creek which flowed into the Royal National Park's Hacking River.

Mr Riach, who was involved in a campaign against mining pollution, felt Heathcote MP Lee Evans and Labor candidate Maryanne Stuart were both "playing politics" around the issues with Metropolitan Colliery.

"Of course they're going to use the jobs argument but in the grand scheme of things, the coal industry is dying," Mr Riach said.

"Those jobs are going to go anyway and we need to have a plan for actually transitioning these workers into new sustainable jobs. It's something that will need to happen. It's something that neither the major parties are willing to acknowledge."

Mr Riach was opposed to the mine remaining open.

"It is my strong view that they should not be a coal mine next to the Royal National Park, the second-oldest national park in the world and such a beautiful protected area," he said.

"This mine should be closed as soon as possible and a plan put in place to phase out all coal and gas."

Mr Evans said the mine was a big employer in his electorate.

"It's one of the oldest coal mines in Australia - it's been there for a long time," Mr Evans said.

"At this stage there's no calling on it to be closed. But the EPA is looking at some severe fines for what's happened with the pollution release.

"They're a big employer so we're going to keep them there, but they have to be a good citizen."

Ms Stuart was also contacted for comment.