Hundreds of high-profile scientists have issued a warning to state and territory governments to tighten land-clearing laws or risk losing precious native species.

The leading conservationists, from Australia and around the world, have issued a declaration to raise the alarm about the potentially deadly impacts of habitat loss.

The petition warned that the New South Wales Government's plans to cut clearing red tape could put more wildlife at risk.

It also expressed concern the Queensland Government's laws to protect vegetation would not pass.

"If we start to relax rules about the clearing of natural vegetation, we are going to lose species, there's no doubt about it," University of Melbourne ecologist Brendan Wintle said.

He has joined hundreds of other scientists in Brisbane this week, presenting research about the impact of habitat loss on native species.

University of Queensland Associate Professor Martine Maron said science was "perhaps being a little sidelined from public debates".

"I think it's just too important an issue to the future of Australia and indeed the world. We're talking about World Heritage matters," she said.

'We want to talk about the science'

The declaration said Australia was one of the world's worst deforestation offenders and called for national reporting of vegetation clearing, better offsets where clearing could not be avoided and restoration of over-cleared landscapes.

Queensland farm lobby group Agforce chief executive Charles Burke argued the status quo was sustainable.

"We want to talk about the science, we want to make sure we stick to the facts and make sure it's not caught up in, sometimes, the conservation rhetoric," he said.

New South Wales Environment Minister Mark Speakman said he was confident with the checks and balances in the new system.

"Yes, it is true that, taken in isolation, any habitat loss is a step backward. But we're aiming for a system that more than compensates for any site-specific habitat loss," he said.

"Our approach involves a massive amount of public investment in new private land conservation.

"Biodiversity's been going backward in New South Wales and farmers have had to deal with excessively restrictive laws. We need a fresh approach."