NSW Labor is to introduce a private member's bill to legislate the state government's net-zero 2050 target that it has yet to write into law.
Opposition Leader Chris Minns says the move will provide certainty for business and industry, and his party's "very reasonable" bill "mirrors similar approaches already taken in Victoria and the ACT".
The NSW government is targeting a 50 per cent reduction in 2005-level emissions by 2030 and net zero by 2050.
The Labor bill seeks to make the targets law and establish a commission to ensure they are met, while seeking bipartisan support from Premier Dominic Perrottet's government to get through.
Mr Minns announced the legislation on Saturday morning although not before Environment Minister Matt Kean issued a release to say the state's National Parks and Wildlife Service would become Australia's first to commit to being carbon positive.
Mr Kean said the plan would ensure the removal of carbon dioxide from the atmosphere by national parks would exceed the emissions they generated by 2028.
"This is a visionary plan that highlights the importance of the national parks in combating climate change alongside the critical role they already play in the conservation of biodiversity providing home to 85 per cent of threatened species in the state," he said.
"It's all designed to position NPWS at the forefront of global environmental efforts."
NPWS will switch to 100 per cent renewable energy, electric passenger vehicles and onsite solar PV, as well as reducing waste and updating refrigeration and air conditioning assets.
It will also trial electric vehicle charging stations in key park areas.
Opposition energy and climate spokesman Jihad Dib meanwhile insisted Labor's bill was needed for the government's net-zero and interim targets because "meaningful action on climate change is too important to open up to changes in government ... we have to go beyond aspiration".
NSW Nature Conservation Council chief executive Chris Gambian is urging the government to support the Labor bill or put up their own.
He says "legislating these targets would also provide greater certainty for clean-energy investors and the general public" and there's currently "nothing to prevent a new government or a new leader scrapping or reducing these targets at the stroke of a pen".
He applauded the government for its ambitious targets but says the council has "always been concerned that they are purely aspirational and not legally binding".
Mr Kean is credited with pushing the government to make aspirational commitments to emissions reduction but Labor is concerned he will soon be leaving the environment portfolio.
Asked on Sky News this week why the parliament had not been committed to a net-zero target, Mr Kean said the government had "in regulation".
He dismissed the question as an attempt to play "word games".
Last week Mr Kean told a budget estimates hearing the state would need new policies to hit the 2050 net-zero target but new technologies and opportunities would arrive to help.