The Berejiklian government's new land-clearing laws have been thrown into disarray after a court found ministers had failed to follow due process.

The NSW Land and Environment Court on Friday declared the government's Land Management (Native Vegetation) Code 2017 to be "invalid and of no effect".

Environmental groups have feared that broadscale clearing rates in NSW would accelerate as they have done in Queensland. Credit:Wilderness Society

"The Court order means that any clearing that has been done under the invalid code since August 25 [last year] is actually unlawful," the Environmental Defenders Office NSW said in a statement.

The NSW Nature Conservation Council launched a legal challenge against the government’s land-clearing codes last November, warning at the time that landholders should exercise "extreme caution" before removing native vegetation on their properties should the new codes be struck down.