WA Liberal Leader Libby Mettam has described as indefensible Premier Roger Cook’s decision to continue funding the discredited protest group Environmental Defenders Office (EDO).

A Federal Court judge this week demolished the evidence of the EDO in its court bid to stop a $5.8 billion government-approved Santos gas project in the Timor Sea.

High Court Justice Natalie Charlesworth said the EDO’s case against the project relied on contradictory and made-up evidence.

“The Cook and Albanese governments cannot in any conscience continue to provide funding to the EDO in the face of the scathing criticism levelled at it by Justice Charlesworth,” Ms Mettam said.

“It is extraordinary in the first place that taxpayer funds are used to pay for an activist organisation to challenge government decisions in the courts, but to continue that funding in light of the finding in the Santos case is astounding.

“The EDO receives millions of dollars in government funding, money it is using to mount what have been shown to be vexatious and fabricated claims.”

Ms Mettam said the Cook and Albanese Governments could not credibly claim to be champions of economic development and the resources sector when they were trying to keep the activist green lobby on side with big cash handouts.

“It shows neither government has the courage of their convictions; they should be backing in their decisions, not funding challenges to them,” Ms Mettam said.

“The finding in the Santos case perfectly highlights the potential for government-funded protest organisations to be weaponised for political purposes.

"The need for strong, effective regulatory oversight is essential. Projects must have social licence and efficient regulation supports this.

"But activism, vexatious legal action and over regulation deliver no positive environmental benefits."