A tenfold increase in penalties for anti-coal seam gas (CSG) protesters who trespass on gas sites has passed in the New South Wales Parliament after a marathon debate.

Key points: New laws may see protesters fined $5,500 for trespassing on sites

New laws may see protesters fined $5,500 for trespassing on sites Survey shows up to 61 per cent of people oppose the laws

Survey shows up to 61 per cent of people oppose the laws NSW Premier says the laws will help save lives

The legislation means people can be fined $5,500 for "aggravated unlawful entry" to certain sites, such as mines.

The legislation also expands the definition of a mine to include gas and gas exploration sites.

The change means anti-CSG protesters who interfere with those sites — including those who "lock on" to equipment during protests — risk a maximum jail sentence of seven years.

The bill was introduced by the Baird Government and passed its second reading in the Upper House on Tuesday night with the support of the Shooters and Fishers Party and Christian Democrat Fred Nile.

Multiple amendments put forward on the bill were voted on Wednesday, with the laws passed by the NSW Government late on Wednesday afternoon.

On Tuesday, hundreds of people rallied outside Parliament House to protest against the changes.

A poll commissioned by the NSW Nature Conservation Council showed 23 per cent of people supported the tougher protest legislation.

But 61 per cent of respondents opposed the increase to police powers and fine hikes for protesters and more than 80 per cent opposed reducing penalties against mining companies.

Nature Conservation Council CEO Kate Smolski said the state government is "wholly out of step" with public opinion.

"It once again shows that the Baird Government bends over backwards to do the bidding of goal and gas companies and are not listening to the genuine community concern," Ms Smolski said.

'Peaceful protests are fine': Premier

When asked on Wednesday whether he thought the laws went too far, NSW Premier Mike Baird said the matter was "quite simple".

"Peaceful protests were fine," Mr Baird said.

"Those that decide to protest and put not only their lives at risk, but workers' lives at risk and try to interrupt businesses that are going about their day-to-day life life.

Dominique Jacobs, of the Knitting Nannas group, locked-on at Santos wastewater plant near Narrabri. ( Supplied: Facebook, file photo )

"We're asking them not to do it and we're putting measures in place to make sure they don't.

"Ultimately it's up to them, anyone that wants to protest peacefully, legally, well there's no problem.

"Anyone that wants to disrupt a business or ultimately act illegally and puts the lives of themselves and others at risk, well we've put these measures in and I think it's appropriate."

The introduction of the legislation came after a series of protests at coal seam gas sites, often involving protesters chaining themselves to equipment, including those by the Knitting Nanas anti-CSG group, which have led to several protesters being arrested.

Greens MP Jeremy Buckingham this week pleaded guilty to trespassing on a Hunter Valley coal mine to make a campaign video.

He was not convicted, but warned to use legal methods to campaign in future.

Existing system is sufficient: Labor

The Opposition's energy spokesman Adam Searle said the existing law adequately met issues of public safety, trespass, obstruction and criminal damage.

He said concerns about recent protests were not a sufficient basis for the changes proposed.

"Mr Baird and his Government ministers simply do not want the community to derail any more of their bad policies through community action," Mr Searle said.

"They're seeking to stifle dissent by passing these harsh and unnecessary new laws."