Greens NSW MP Jeremy Buckingham says the NSW government should hand back the money following the backlash against the $1-billion open-cut coal mine in the NSW Liverpool Plains.

There's been a furore from local farmers, anti-mining groups - and even federal Agricultural Minister Barnaby Joyce - since the Abbott government granted the mine's conditional approval.

Mr Buckingham said if Shenhua was paid back the $300-million exploration licence fee and sold the $200 million-plus worth of farmland it has bought, it should recover up to $500 million of the $700 million it has spent.

"It's time someone in power put the national interest first and protected the best agricultural land in Australia," Mr Buckingham said in a statement.

Mr Joyce said he had written to Mr Baird about the project near Gunnedah, which must be given final approval by the NSW government.

The approval of a mining lease, which Shenhua needs, is a relative formality and legally cannot be refused except in very exceptional circumstances.

Comment has been sought from Shenhua.

Meanwhile, Environment Minister Greg Hunt insists he and Barnaby Joyce are still buddies despite their differences over the approval.

Mr Hunt says he respects the Agriculture Minister for voicing his concerns.

Mr Hunt, who gave the federal sign-off for the project without Mr Joyce's knowledge, said they've spoken twice in the past week.

Theirs was an "incredibly positive, civil relationship", he insisted. AAP