A report into the system by which the NSW government is compulsorily acquiring millions of dollars worth of land for controversial projects such as the WestConnex motorway may never be released, confidential documents show.

The report by David Russell SC was commissioned by then-finance minister Greg Pearce in May 2012 and released in February 2014, but has been kept secret ever since.

All but two of the independent review’s recommendations have been rejected under advice from an interdepartmental committee, according to documents obtained by the Labor opposition.

Finance, Services and Property Minister Dominic Perrottet wrote to Premier Mike Baird on December 18, 2015 to advise him that the key concern of agencies such as Roads and Maritime Services was that “a number of the recommendations would likely have adverse impacts” on current infrastructure projects.

These include increased disputation, valuation complexity, additional costs and delays, he said.

“On this basis, I recommended that at this time no further action be taken to address the review report,” Mr Perrottet said.

Two recommendations in the report, including the introduction of a clear explanation of the land acquisition process and the opportunity for a face-to-face meeting with land valuers, have been acted upon.

Hundreds of millions of dollars worth of private properties have already been acquired by the government to make way for a swag of infrastructure projects including the Sydney light rail and WestConnex motorway.

The compulsory acquisition and land valuation system has been criticised as unfair to landowners because it offers compensation hundreds of thousands of dollars below market value.