When the curtains rise at a powerful parliamentary inquiry into a $40 billion NSW rail entity set up to artificially inflate the NSW budget, the big four consulting firms will be hauled into the spotlight.

The inquiry’s chairman, Greens MP David Shoebridge, described the parliamentary inquiry over the next two weeks as “a moment when we get to look under the bonnet and see what really went on while the government worked with carefully picked consultants to cook up the scheme”.