Premier Ben Carroll is trying to claw back $2 billion on the Suburban Rail Loop project by scrapping extra car parking, a second station entrance and pedestrian bridges.

Infrastructure adviser Dr Eric Keys told 3AW Mornings host Shane McInnes he fears they are making critical mistakes.

Press PLAY to hear why Keys believes these mistakes could be critical

“$2 billion out of what we are told is a $35 billion project is less than 10 per cent and yet the connections that are getting cut are critical to the way people will experience the service once it opens,” he said.

Images: Darrian Traynor/GettyImages, @Suburban Rail Loop/Facebook