Shortly before Christmas, a long-neglected industrial site on Darley Road, just near the City West Link, was transformed into a Dan Murphy's bottle-shop.

But then, after only a couple of months of wine and beer sales, it emerged the government wanted to acquire the bottle-shop for a tunnelling site for the WestConnex motorway.

Surely they would have known? Why did the government, which has been committed to WestConnex for five years, allow a bottle-shop to be built when it knew it would likely soon tear it down?

It turns out they did know. According to documents obtained by community campaigners opposed to the motorway, the multimillion-dollar business was allowed to get established in seemingly full knowledge it may soon be dismantled.

The Darley Road site is owned by RailCorp. But a company called Tdrahhciel (Leichhardt spelled backwards) owns a lease on the site and had been trying to establish a shopping precinct there since 2007. Tdrahhciel signed a sub-lease with Dan Murphy's, which is owned by Woolworths, in 2014.

The owners Andrew Wilsmore, a spokesman for Woolworths' Endeavour Drinks Group, said Dan Murphy's was contractually obligated to continue to make its best efforts to open the store at Leichhardt, even when it emerged the site may be acquired.

On August 15, representatives from RMS contacted Shane Barr, the owner of Tdrahhciel to tell him of the prospect of the Darley Road site being required for WestConnex.

By October 11, according to notes obtained using freedom of information laws by community group Leichhardt Against WestCONnex, RMS told Mr Barr by phone Darley Road had been "identified as the preferred site".

Nevertheless Mr Barr still could not get straight answers as to whether, when and how RMS would be acquiring the site.

"For 7 years I have been treated with destain [sic], arrogance, and I will say ignorance," Mr Barr wrote to his RMS contacts on October 14. "By public servants, on Tuesday I was told ??? that day I would receive in writing the decision that these servants wish to acquire our lease property," he wrote. But that information was not forthcoming.

By November 4, Mr Barr received in writing a notice that WestConnex "will unfortunately necessitate the acquisition of the property."

It was only after issuing this notice to Mr Barr that Sydney Motorway Corporation raised the prospect of using an alternative site next to a Leichhardt high school. SMC has since said it would not use the school site.

For Leichhardt Against WestCONnex, the document trail demonstrates that while community groups and representatives were told repeatedly last year that no decisions had been made about the Darley Road site, the government was preparing for the acquisition.

"We now know that when SMC and RMS were telling LAW and the community this, behind the scenes the statutory acquisition process for 7 Darley Road had commenced," a spokeswoman for Leichhardt Against WestCONnex, Jennifer Aaron, said. "This is yet another breach of trust by the government and its agents."

Nevertheless, Roads and Maritime Services and SMC will still not confirm the acquisition of the site. A preliminary design for that section of the motorway was released on Friday, and refers to the Darley Road site only as a "potential" tunnelling location.

A spokesman for RMS said the government was also looking at using the western end of the Rozelle rail yards as a potential tunnelling location. The SMC had previously ruled out the Rozelle rail yards because of conflicts with light rail operations, but the spokesman said SMC was "currently carrying out environmental and technical investigations to determine suitability".

Mr Barr has previously told Fairfax Media the compensation due his company and Woolworths could be in the order of $50 million.