Troy Grant, NSW Nationals leader and Deputy Premier, was more than a tad optimistic when he called for "natural opponents" of the government's new biodiversity conservation bills to use the two-month consultation period to improve them.

The new bills were "a balanced and very good outcome", and those who took them as a signal to let rip with their D9 bulldozers didn't belong in NSW, the former police inspector declared.

"If they want to be a cowboy, they can move to Queensland," Grant said on Tuesday.

His comments, though, merely highlighted the controversial nature of the bills, which will replace NSW's Native Vegetation, the Threatened Species Act and parts of the National Parks and Wildlife Act.

Queensland, in fact, is trying to reverse a loosening of vegetation laws that had led to a doubling of annual clearing within two years of their introduction by then Premier Campbell Newman to 300,000 hectares  – or more than 100 times the City of Sydney.

"It's sad and ironic that the NSW government is pointing to the laws introduced by their Queensland Liberal National colleagues to argue their own new laws are not nearly as extreme, reckless and destructive," Steven Miles, Labor's Environment Minister, tells Fairfax Media.

"Queensland's experience shows what will go wrong if they water down their land-clearing protections as they plan to do."

With the number of threatened plant and animal species in NSW ticking past 1000, Environment Minister Mark Speakman reasonably argues that "biodiversity has gone backwards in the past 20 years".

"What we have in place has not been working," he says. "So we need something better."

However, conservation groups say what's on offer will be worse – possibly much worse.

The government will introduce codes aimed at giving landowners more scope to "self-assess" what should be spared or not. It is hoping the carrot of cash to reward those who protect habitat on their land – $240 million over the first five years, rising to $70 million a year after that – will do more than the sticks now used.

Contents aside, the release of the draft bills now is unfortunate timing. Ian Turnbull, a farmer from Moree, is before the Supreme Court, facing murder charges for allegedly gunning down Glen Turner, an Office of Environment and Heritage staffer who had been inspecting land clearing in 2014.

A section of the Nationals has been campaigning hard to reverse the 2005 Native Vegetation Act, that among other things, requires farmers to "maintain and improve" biodiversity if they clear land.

Derek Schoen, president of NSW Farmers, welcomes the repeal of an "unworkable and detrimental" Act: "It was just bureaucratic red tape. Most people couldn't get through the process."

He's annoyed, though, that farmers won't have the maps – possibly until next year – showing whether they will still need approval to clear. "It's a big mistake," he says. "It's been a long process. There's been a lot of time to get the maps."

Others, though, point to weaknesses in OEH mapping that suggest they are far from ready.

Rachel Walmsley, from the Environment Defenders Office NSW, says OEH officers have told her "so much more can be cleared under codes, regardless of the condition".

Land-clearing – the main cause of species decline – will become far less transparent and won't allow third-party review. Major decisions will be made by relatively under-skilled Local Land Services staff, critics fear.

An OEH spokesman, however, says there would no effect on existing appeal rights relating to developments and environment assessment in the new bills.

Also, much of the control shifts to the Department of Primary Industries – with Nationals' Niall Blair as minister –  rather than the Department of Planning and Environment, contradicting recommendations of the 2014 review of biodiversity legislation.

Secrecy also shrouds the biodiversity offsets that are meant to compensate for habitat lost. The OEH will run this part but is not required to disclose what's being traded off and at what price.

"Once it goes into a box owned by OEH, no one will know what's in it," says John Hunter, an ecologist with the University of New England.

The OEH spokesman, though, said the government is committed to ensuring information about offsets is transparent and a register would make some details public.

"The Environment Agency Head can choose to not include certain information on the public register if it is in the public interest to not do so," he said. "This may include restricting public knowledge on the location of particularly sensitive biodiversity to ensure its protection (as was the case with the Wollemi Pine)."

Some land has been "offset" at least three times, one ecologist in the public sector tells Fairfax Media: "So long as [the flora species] doesn't become technically extinct, you can gut it."

Among documents under review is one that indicates land placed under voluntary conservation agreements could be re-classified by later owners as an offset, much to the dismay of landholders such as Jocelyn Howden.

Since 1989, Howden and four neighbours have run a wildlife refuge at Glenorie, near the Hawksbury River, protecting Sydney grey gums, yellow bloodwoods and the king parrots and other creatures that live in them.

"You've gone to this trouble, committed yourself and your property to protect the land and its biodiversity for all time," she says.

She worries landowners thinking of conservation covenants may be put off: "That would be tragic. They will say 'what's the point?'"