Almost $100,000 was spent on a report into the system by which hundreds of millions of dollars worth of land is being compulsorily acquired for projects such as the WestConnex motorway, but which the NSW government refuses to release.

The report is being kept secret as the number of land valuations associated with WestConnex surged last year as work on the project intensifies.

Protestor Bill Holliday refusing to leave a home in Haberfield due to be demolished for WestConnex.

The report by David Russell, SC, was commissioned in May 2012 by then finance minister Greg Pearce.

Its terms of reference included recommending "a set of principles to guide the process for how acquisitions of real property should be dealt with by government".