Prime Minister Julia Gillard met coalminers in Lake Macquarie in her latest bid to sell the controversial tax.

It followed visits from Opposition Leader Tony Abbott and Nationals senator Barnaby Joyce last week, who toured a Hunter mine and further outlined their opposition to the tax.

Ms Gillard and Climate Change Minister Greg Combet met miners at Centennial Coal’s Mandalong Colliery in south-west Lake Macquarie.

The pair were calm and softly spoken, despite public pressure and a backlash against the tax.

‘‘This is the right decision for the nation’s future,’’ Ms Gillard said of the tax.

Ms Gillard had the support of Centennial miner Stuart Macdonald, 50, of Cooranbong, who said: ‘‘I’m a realist, I believe in climate change, so a carbon tax has to come in’’.

His colleague, John Simm, 58, of Weston, said: ‘‘It does worry me because there’s a lot of young families who it could affect’’.

Miner Troy Potter, 32, of Bar Beach, said: ‘‘The coal industry is going really well and they’re going to wind it back with a price on carbon’’.

Ms Gillard insisted that was not the case, saying the coal industry had a ‘‘great future’’.

She promised the miners their jobs would not be threatened.

‘‘They’ll be here mining coal as long as this mine lasts,’’ Ms Gillard said.

Centennial chief executive officer David Moult said 300 jobs were under threat at Myuna and Mannering coalmines in Lake Macquarie, if Centennial could not pass on carbon taxes to power stations.

Mr Moult said it was possible the mines could close if they had to absorb carbon taxes applied to methane emitted from the mines.

‘‘The economics of them would be very difficult to stack up,’’ he said.

Ms Gillard and Mr Combet made no commitment to support Centennial passing on its costs to power generators.

‘‘For the people who flick on the lights and use power, we have factored in a 10per cent increase in power costs,’’ Ms Gillard said.

Tax cuts and other government payments to people would cover those costs, she said.

Mr Combet said Centennial was eligible for assistance from the government’s $1.3billion package for coalmines with high methane levels.

Centennial said any money it received from that fund would offset, but not fully cover, its costs.

Mr Combet said Centennial was working on technology to remove methane emissions from its mines, but the company said the technology was five to 10 years away from commercial operation.

Greens senator Lee Rhiannon also visited Newcastle yesterday, beginning a tour of NSW by handing out flyers in Newcastle mall.

‘‘We’ve always said to be serious about climate change, you need to have a plan for coal,’’ Senator Rhiannon said.

‘‘But at the same time I acknowledge the huge contribution coalminers have made [in the Hunter].

‘‘But life changes, we’re in the midst of a challenging time and we need governments to also have the political will to effect that change.’’

Senator Rhiannon said Hunter people had an understanding of the need to move towards renewable energy.

‘‘We’re not going to have all the same jobs, but the Greens’ commitment is that everybody should have a job and should not lose a job.’’

Senator Rhiannon sat alongside Newcastle councillor Michael Osborne and Newcastle Trades Hall Council secretary Gary Kennedy at a press conference. Mr Kennedy said he believed the government would have success selling the package.

Ms Gillard also visited Maitland’s heritage mall, where Hunter MP Joel Fitzgibbon said she was ‘‘treated like a pop star’’.

Paterson MP Bob Baldwin said it was ‘‘time for the Prime Minister to start listening to the people, not lecturing them’’.