CHANGE your policies on gas - or suffer the electoral consequences.

That was the pre-election warning issued by Gasfield Free Northern Rivers to local Nationals yesterday.

Campaigners have collected 6000 individually signed postcards from across the region calling for a gas ban on the Northern Rivers in the last six weeks.

Taking delivery of the postcards were candidates for the seat of Lismore, Labor's Isaac Smith and the Greens' Adam Guise, alongside Ballina independent candidate Jeff Johnson.

>> NSW Election 2015 full coverage

Both Mr Smith and Mr Guise have vowed to suspend or ban unconventional gas on the Northern Rivers, and the Greens-Labor preferencing deal means they are combining their votes in an attempt to topple Lismore MP Thomas George.

Mr Guise said the postcards were the "culmination of four years of tireless campaigning" by the community who stood against the industry.

"We live in one of the most beautiful regions in the world and it's worth protecting," he said.

He appealed to voters to use their ballot power to secure the region "gasfield free forever in perpetuity".

MORE ON CSG

• Lock the Gate Alliance says NSW election hinges on CSG
• Metgasco scraps Elk merger deal and wants its $1.69m back
• Frackman picks up Byron Film Fest's top award
• ALP won't break ties to CSG giant

Gasfield Free organiser Elli Bird appealed for the Nationals to change their policy and make similar commitments to Labor and the Greens.

She called for the government to "rewrite" the Onshore Petroleum Act to ban unconventional gas on the Northern Rivers.

But Mr George has said the State Government risked a massive lawsuit from miners if it issued an overnight ban on the industry.

"Our advice is you can't cancel licenses, and if you did you'd have legal action to settle it," he said.

But Mr Guise said the Petroleum Onshore Act had provisions for the government to cancel licenses without compensation provided there had been breaches.

"None of this argument about compensation washes... (Premier) Baird said he wants the industry to go ahead; this is a government who wants to push CSG in NSW," he said.