In the Coalition ministry meeting yesterday, Mr Abbott was forcefully told that Nationals frontbenchers were adamant farmers' rights had to be protected over miners'.

While Mr Abbott said the opposition would not back a Greens move to bring in new restrictions on the coal seam gas industry, Senator Heffernan called for the minor party to instead be patient and await the findings of a Senate committee inquiry into the effect of the industry.

Senator Heffernan said the constitutionality of the Greens move was "questionable" and the issue of land access for mining was a state matter.

But he told The Australian Financial Review "there were serious flaws with the whole approval process [for coal seam gas mining], which was set against a background of a lack of knowledge by departments and the CSIRO about its long-term effects on water aquifers".