FEDERAL Agriculture Minister Joe Ludwig has been criticised for failing to state a position on coal-seam gas mining.

As a farmer blockade stopped mining giant Santos from accessing a farm on the Liverpool Plains in NSW last week, the Greens and Nationals have attacked the federal minister over the issue.

Senator Ludwig last week called for a "harmonised" approach to CSG - suggesting state governments should adopt a uniform approach to CSG development.

But he did not say what he thought the approach should be and his office did not respond to The Weekly Times' request for comment.

Nationals Senate leader Barnaby Joyce said Senator Ludwig was "hoping for a lot of talking, which leaves us with the status quo".

He said the Agriculture Minister should detail what approach the nation should take to CSG development in agricultural areas.

"Our position is it shouldn't be allowed to destroy aquifers, intrude on to prime agricultural land, shouldn't interfere with quiet enjoyment of residential areas and farmers should get a proper (financial) return, because at they moment they're getting ripped off," Senator Joyce said.

Greens environment spokeswoman Larissa Waters said harmonisation would not reverse the states' "short-sighted grab for CSG royalties" and that farmers should have the right to refuse mining companies access to their land.

"Harmonised poor standards are still poor standards, and will not address the community's concerns about the rapidly expanding industry," Senator Waters said.

"Food security and water are national issues that deserve protection at the federal level."

Santos has bought CSG company Eastern Star Gas, the chairman of which is former Nationals leader and deputy Prime Minister John Anderson.

And NSW Farmers remains livid the state's Coalition Government appears to have dumped a pre-election promise to protect farmland.