The fires scorched about 5.5 million hectares in NSW, adding to the threat posed to dozens of endangered plants and animal species.

"In January 2019, the NSW Premier requested independent, evidence-based advice from the Natural Resources Commission about the policy review point for the land management and biodiversity conservation laws," a spokesman for Energy and Environment Minister Matt Kean said, adding it will consider the commission's advice "carefully and will respond".

"New clearing approvals must be paused until the government can put on the table real reforms to ensure this massive biodiversity loss can't continue."

"After a summer of bushfire hell and the worst drought on record, accelerated land clearing is just adding to devastating biodiversity loss," Mr Field said.

According to the report, more than 37,000 hectares were approved to be cleared in the 2018-19 year, or almost 13 times the annual average rate of approval to clear 2700 hectares in the decade prior to the law changes in 2016-17.

There were also signs of an acceleration of approvals, with permits rising from 25,247 hectares in the fourth quarter of 2018 to 43,553 hectares in the following three months. That jump came after the government introduced new codes.

The audit also touched on the difficulties government compliance officers have faced keeping track of what land was being cleared. For instance, the commission identified 7100 hectares of "unexplained" clearing during the six months between August 2017 and January 2018, or about 60 per cent of all land clearing.

The government has also failed to act on a pledge to set aside between two and four times the areas of land approved for clearing. In nine of the 11 regions, the set-asides ranged from 6 to 69 per cent of the approved hectares, the audit found.

Much of the land clearing has involved approvals for thinning to allow pasture expansion. Under this rule, such clearing has amounted to a “statewide risk to biodiversity”, and the “policy intent of the reforms is not being achieved”, the audit found.