Land-clearing in NSW jumped in the year prior to the introduction of native vegetation laws, with one region recording a 40-fold surge in the removal of woody land cover, new government data shows.

Some 20,200 hectares were cleared for crops, pasture or thinning - or about 70 times the size of Sydney's central business district - in the 2016-17 year, according to information provided to the Herald under freedom of information laws. That rate was more than twice the annual average over the previous seven years.

Illegal clearing in north-west NSW; rates of native vegetation destruction ramped up in the two years to June 2017.

Forestry also accelerated in 2016-17, rising two-thirds compared with the average from 2009-10.

The state's north and west dominated the clearing rates, with the Wentworth local government area in the Riverina registering the fastest increase. Woody vegetation cleared for crops, pasture or thinning leapt to 4454 hectares, up from an average of 112 hectares during the years from mid-2009 to mid-2016, the satellite-sourced data shows.