A Berejiklian Government MP has revolted against his party's policy, backing his "local fishing community" over his Government's plan to introduce 25 new marine park sites across the state.

Adam Crouch, the Liberal MP who holds the Central Coast seat of Terrigal, ignored his party's line and released a statement calling the NSW Government's proposal, announced last month, "too extreme".

The plan, which is up for public feedback until the end of the month, involves a patchwork of 25 sites of variable conservation levels between Newcastle and Wollongong.

Although not yet set in stone, proposal is set to affect some recreational fishing activities "particularly shore and boat-based line and trap fishing and hand gathering".

The proposal has flagged potential new recreational fishing special-purpose zones, a review of existing closures and additional artificial reefs.

While is has been welcomed by the Greens, the Shooters Fishers and Farmers Party has threatened to turn the marine park proposal into an election issue by running candidates in every Liberal-held seat, including Mr Crouch's, unless it is dropped.

An aerial view of the existing marine park around Port Stephens ( Supplied )

Mr Crouch said fishing was an "integral" part of the region's lifestyle and economy.

"My concerns align with many of the comments being made by our local fishing community, whom I support," he wrote in his statement.

"While it's just a proposal right now, I want to be clear, I believe what's on the table is too extreme and won't work for my community."

Shooters Fishers and Farmers MP Robert Borsak described the backlash amongst recreational fishers as "phenomenal".

A Facebook group called Stop The Lockout, created two years ago, now has more than 30,000 members including 10,000 amassed in the last month.

The 'Stop The Lockout' Facebook page. ( Facebook: Stop The Lockout )

"What the Liberal Party has done is woken the sleeping giant of recreational fishers," Mr Borsak said.

He predicted more Liberal MPs would follow Mr Crouch's lead even though they may not have any real say in the policy.

"This is ham-fisted politics of the worst kind from their point of view and I thank them very much for doing it."

NSW Greens spokesman Justin Field said the fishing "lobby" — the tackle industry, big TV fishing personalities and the Shooters Fishers and Farmers Party — was not representative of the breadth of views of recreational fishers.

"They're spreading so many lies and mistruths about the Government's proposal," he said. "I am concerned that the Government will water down what is already the bare minimum for putting aside areas for marine conservation."

But Minister for Primary Industries Niall Blair said Mr Crouch's comments — even though they were in the same government — were "part of the democratic process".

"That's what consultation is about," he said.

"An independent group of scientists made the proposal – and we consult before we make a decision. That's how this government operates."

Between 90 and 95 per cent of the Sydney Marine Park area would remain open to recreational fishing, Mr Field added.

Labor leader Luke Foley this week declared the opposition would not "lock out" recreational fishers and committed to a "multi-use" marine park.