It’s another day and another controversy for the increasingly embattled head of the $17 billion WestConnex consortium, Dennis Cliche.

This time, Cliche has been forced to admit that he falsely claimed NSW chief scientist Mary O'Kane was in favour of the WestConnex exhaust ventilation stacks after warnings that his comments publicly questioned both her integrity and independence, according to a story in the Sydney Morning Herald (SMH).

This follows his earlier comments this month, where he was also quoted by the SMH saying the reintroduction of tolls on the newly-widened M4 motorway was “exciting”, a move which has been described by some politicians and social commentators as being "a tax on western Sydney motorists".

Moreover, when describing the motorway’s controversial ventilation stacks during a recent speech to the Infrastructure Partnerships Australia conference, Cliche joked that’s "where all those nasty exhaust gases come up, you know, and kill the community and all the rest of it", and insisted that he “would have no problem living underneath one".

At the same conference, he was also quoted claiming that “the submission from the Chief Scientist of NSW was extremely complimentary on the [environmental impact statement] work we had done on our ventilation facilities,” which is what O’Kane objected to.

Fairfax Media has reported that Professor O'Kane wrote to Cliche shortly afterwards to express alarm at the remark, branding his comments "false and misleading that called into question her integrity and independence as the NSW chief scientist and engineer."

While this latest gaffe has now been settled by Cliche providing an apology, this all comes at an inopportune time for the NSW government, which is looking for buyers for its 51 per cent stake in the Sydney Motorway Corporation, the builders of WestConnex and where Cliché is chief executive.

While there were many public reactions and comments about Cliche’s seemingly magnet-like abilities to court controversy, perhaps one of the most succinct was by architect Shaun Carter, who posted on twitter: "WestCONnex CEO remarks completely consistent with the project. The GOLD standard of how NOT to deliver a public project. Perhaps it is time he was moved on."