It's a descriptive expression, capable of interpretation to suit the opinions of both major camps in the gas debate.

To those companies now rushing to prove resources and planning pipelines, power stations and export terminals, the description conjures notions of vast energy profits.

To those who are worried about the potential effects of thousands of gas wells on the nation's underground water resources, the desert imagery matches their fears.

Mr Crean, in the remainder of his Saudi Arabia speech, said the only things a federal minister could sensibly say on the subject.

The first point is that, taken as a fuel, gas is cleaner than most other fossil fuel options. The second point is that Australia's gas reserves are enormous and extremely valuable.

It is the third point, however, around which the debate now turns. Drilling for gas will bring environmental costs. The big difficulty is that those costs are not yet possible to properly quantify.

Proponents of drilling cite numerous examples where they have pierced through aquifers to reach gas-bearing rock-layers with no deleterious effects. But it isn't possible for them to deny that cases exist where mistakes have been made, seals have failed, and underground water resources have been ruined.

In encouraging and approving the exploitation of gas reserves, the precautionary principle must be applied. That means that more care must be taken evaluating proposals to extract gas from areas where underground water is important for human consumption, for agricultural purposes or to maintain important ecological assets.

If such proposals are approved it must be with extremely stringent safeguards. Governments - both state and federal - must be prepared to identify proposals that are too risky and refuse them.

Fullerton Cove, because of its proximity to the Tomago Sandbeds that remain a vital part of Newcastle's water supply, is surely one area where the greatest possible caution should be applied.