The Greens say they now have documents to prove the State Government was going to send up to 800 police officers to the anti-gas protest site at Bentley.

New South Wales MP, David Shoebridge, says he used Freedom of Information Laws to obtain documents from the government and police department.

He says Metgasco wanted the protest camp disbanded in May so it could start drilling a test well near Lismore.

Mr Shoebridge says the Northern Rivers community should be concerned.

"Well, I think anyone would be very nervous of the prospect of 800 police from the Tactical Response Squads, the Riot Squads, Public Order Squads, being sent into your local area," he said.

"That's an extraordinary proposition to turn up into your neighbourhood, particularly if you live in a law-abiding and peaceful society like we have here in NSW.

"This shows I think two things, how close to the big miners, particularly the coal seam gas miners, that the New South Wales Government has become.

"But it also shows how little regard the government really has for the fundamental right to protest.

"That they're willing to throw the entire power of the state behind the police to break-up a peaceful protest.

"That's the really troubling matter here."

Local anti-gas campaigners are challenging the State Government to reveal more about the planned police response.

The cost of the operation is described as a matter for the Police Commissioner, although it's made clear the gas company would not be made to pay.

Ian Gaillard, from Gasfield Free Northern Rivers, says the government should come clean about how much it was willing to spend.

"If it had gone ahead, conservative estimates would have put it at $10 million for the operation, and other estimates would have put it at over $14 (million)," he said.

"So it would have been a massive amount, and a massive impost on we the taxpayer to send us these police to protect this company."

The ABC is waiting on a response from the state's Police Minister and Police Commissioner.