The number of prosecutions for illegal land clearing in NSW has dropped sharply, according to documents obtained under freedom of information laws.

The Berejiklian government, however, continues to withhold data on how much land has been cleared, particularly since its 2017 overhaul of native vegetation protection laws that environmental groups say loosened land-clearing restrictions.

Workers clearing trees in forest land.

The Liberal-National government, in power since 2011, commenced 10 land-clearing prosecutions in the 2014-15 financial year, a number that dived to just two in each of the subsequent two years, the documents from the Office of Environment & Heritage showed.

There have been no prosecutions started since the new laws came into force last August 25, according to the documents, which were obtained by Labor.