The biggest change to legislation governing biodiversity and threatened species in New South Wales in a generation is being criticised on both sides of the debate.

In the 1990s major reforms put an end to broad-scale land cleaning in NSW.

But the laws are being reworked.

The Government insists it will be a boon for development and biodiversity, and that the legislation is based on recommendations of an independent expert panel.

But conservationists say the proposals are deeply flawed, could see a return to broad-scale land clearing, and are designed to placate a handful of farmers.

NSW farmers say it still isn't clear how the changes will work, as the maps that will dictate how the land is managed still haven't been released.

In Moree and Walgett, in the state's north-west, there has been mounting pressure from farmers to get more control of their land in an attempt to boost productivity.

Sorry, this video has expired Farmer Oscar Pearse told reporter Liv Casben that the trees get sick, despite the laws.

Oscar Pearse, who grows chickpeas at Moree, is one farmer supportive of change.

"The native vegetation laws that have been in place for the past 20 years are effectively halting farmers from adapting and using modern technology, from adapting to modern and emerging markets," he said.

"The laws need to acknowledge that productivity increases and productivity benefits can be made without large environmental damage.

"In fact, there's the potential to improve the environmental outcomes.

"On our farm, specifically, that's largely about better weed and pest management."

Mr Pearse sprays his chickpea crop to kill-off disease, but said some trees on his land make it difficult for him to carry out the work.

He said isolated trees were obstacles that meant he was forced to use inefficient practices, including laying more chemicals, and using more fuel.

Additional spray also had a negative impact on the isolated trees, leaving them sick, he said, meaning he would ideally like to be able to remove the trees that were hindering agricultural work and plant other elsewhere, offsetting removal.

'We need more respect for the bush'

Sorry, this video has expired Glenn Morris said he went to Sydney to call for respect for the bush.

But not all members of the farming community are supportive of the changes.

Organic beef farmer Glenn Morris said the draft law did not go far enough to encourage sustainable farming.

Mr Morris recently took his concerns to Sydney and stopped traffic by riding his horse on the Sydney Harbour Bridge.

"I was down there to raise the bar," he said. "To say that we need more respect for the bush for soils in general.

"The way I look at it, we need a complete re-vegetation policy for NSW, not a policy that reduces vegetation further.

"But I don't see trees as being inefficient.

"I see trees as being magnificent, processing water and storing carbon and homes for wildlife and we really need to completely rethink the way we treat vegetation."

Glenn Morris slowed traffic for several hours when he rode a horse across the Harbour Bridge. ( AAP: Dan Himbrechts, file photo )

Biodiversity threatened: conservationists

Conservationists have also aired concerns about the impact the laws might have on environmental biodiversity.

They are supportive of the current laws, arguing they have wound back land-clearing rates by as much as 40 per cent, protecting the land and more than one million native animals on it.

Native Conservation Council chief executive Kate Smolski said the newly-proposed laws would prioritise big business over the environment.

"This package has everything to do with fast-tracking land clearing for developers and larger agribusiness, and very little, if anything, to do with actual biodiversity conservation," she said.

"Nothing is too precious, nothing is off limits from clearing."

Ms Smolski said the changes would also put native species at risk.

"The main loser in this is the thousands of threatened species we have here in NSW," she said.

"We know if this reform package goes through, it is going to drive greater extinction and push species to the brink."

Professor Hugh Possingham is part of the Biodiversity Review Panel that reviewed the Native Vegetation Act.

He has now joined with the Wentworth Group of Concerned Scientists in speaking out against the draft legislation, concerned it could see a return to excessive clearing.

"The new codes allow for habitat loss without compensation to the environment," he said.

"This will lead to a loss of the topsoil that provides food for people, declining freshwater quality that provides drinking water to people and increased chances of species extinction."

Hosing down the criticism, NSW Environment Minister Mark Speakman said there would be protections to stop over-clearing.

"This is not Queensland. There are numerous checks and balances to ensure we will not have runaway land clearing there are speed limits on how much you can clear," he said.

It is unclear exactly what the final legislation will look like, but it is certain there will be more debate its impact.