The NSW Farmers Association has called on Federal Agriculture Minister Barnaby Joyce to take the community's concerns over an open-cut coal mine on the Liverpool Plains to Prime Minister Tony Abbott.

Federal Environment Minister Greg Hunt approved the Shenhua Watermark project yesterday, under strict conditions.

Farmers claim the project will leave a massive hole in the most fertile agricultural land in the country.

NSW Farmers Association President Fiona Simson said Mr Joyce needed to step up.

"We hope that Barnaby Joyce will now take that forward, take that to the cabinet, take that to the Prime Minister and stop this mine in amongst Australia's most significant underground water resource," she said.

The NSW Government had approved the project earlier this year.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 5 minutes 27 seconds 5 m Listen to Sarina Locke's report for ABC Rural. ( Sarina Locke ) Download 2.5 MB

The ABC spoke to several farmers who said they voted for the Nationals in the state election earlier this year because they trusted the Coalition to listen to their concerns and not approve the mine.

Key facts: Shenhua's coal mine The open-cut coal project is valued at $1.2 billion

The open-cut coal project is valued at $1.2 billion 10 million tonnes of coal will be extracted a year

10 million tonnes of coal will be extracted a year The mine has a 30-year life, with extraction expected to end in 2046

The mine has a 30-year life, with extraction expected to end in 2046 159 million tonnes of coal will be mined over 30 years

159 million tonnes of coal will be mined over 30 years The project is 280km by rail from the Port of Newcastle, from where the coal will be exported

The project is 280km by rail from the Port of Newcastle, from where the coal will be exported Mining operations will run 24 hours a day, seven days a week

Mining operations will run 24 hours a day, seven days a week There will be five blast events a week once mining operations are established

There will be five blast events a week once mining operations are established The project is expected to employ 600 construction staff and another 400 to run the mine Source: NSW Planning and Environment and Shenhua Watermark

During the campaign, Premier Mike Baird visited the region and met with locals at farmer Andrew Pursehouse's home.

"Mike Baird sat at my table and told a group of farmers he would take a personal interest in this," he said.

"Well, it's now July and we haven't heard a word from him since."

Mr Pursehouse said he and other farmers were "gutted" the Shenhua mine had been given the green light and they do not believe the politicians understand the agricultural importance of the black soil plains.

Susie Lyle said farmers felt the Government had abandoned them.

"I live on the Liverpool Plains ... with the iconic koala, Aboriginal archaeological sites and we are coming second to a communist state-owned company," she said.

Farmers had their chance at March poll: Shenhua

Shenhua Watermark project manager Paul Jackson said voters had an opportunity to support an anti-mining agenda at the March poll.

"The real straw poll was the March election where the local member, the Nationals member, had a 4 per cent increase in his majority and the independent, who openly ran on an anti-mining, anti-Shnehua platform, lost 29 of the 30 ballots," he said.

Independent candidate Peter Draper ran on an anti-mining campaign in the seat of Tamworth and lost.

The Nationals' Kevin Anderson won with 61 per cent of the vote.

There are questions as to whether the support for conservative candidates would be challenged at the federal level.

The former MP for the federal seat of New England, Tony Windsor, said he was considering a political comeback following the mine's approval.

"I am considering it [but] haven't made a firm decision one way or the other," he said.

Mr Windsor added the only way farmers would get change on the issue was to vote.

He said change was happening on the north coast of the state because people there turned against the National Party and voted for the Greens.

"This is nothing to do with process, it's all to do with politics," he said.

Mr Windsor would face a contest against Agriculture Minister Barnaby Joyce who has also been critical of the Federal Government's decision to approve the open-cut mine.