The report by wildlife conservation group WWF and the NSW Nature Conservation Council found since the repeal of the state's Native Vegetation Act in 2017, the rate of native bushland clearing in Moree and Collarenebri has nearly tripled.

The NSW government replaced the law with controversial land-cleared codes which allow property owners to clear sections of native bushland without prior environmental assessment.

The NCC and WWF compared satellite images of 22,173 sq km of land around Moree and Collarenebri for the report, which was released on Friday.

The extensive clearing of koala habitat is "detrimental" for the popular species which is listed as vulnerable to extinction, WWF-Australia conservationist Stuart Blanch said.

He warned that koalas faced extinction in NSW as early as 2050 with 5246 hectares of koala habitat around the two farming communities destroyed between mid-2017 and mid-2018.

"We have to stop this excessive tree-clearing if we want to keep koalas alive in the wild for future generations," Mr Blanch said in a statement on Friday.

NSW NCC chief executive Kate Smolski said the report was just the "tip of the iceberg" as it only looked at a fraction of the state.

She blamed the state government for "opening the floodgates" to the destruction of koala forests.

The report also found nearly 7000 hectares of habitat for the vulnerable-listed painted honeyeater was destroyed in the same area.

The NSW Department of Environment said it would investigate any reports of illegal land clearing and noted it has in place an "effective" regulatory compliance program where all potential breaches are assessed.

A department spokesman said the new laws have established tougher penalties for illegal clearing and harming threatened species with Local Land Services working with the farming community to help it understand the changes.

The land clearing laws have twice been challenged in the NSW Land and Environment Court by the NCC.

Australian Associated Press