You get assurance the equipment / service will operate or you withhold payment until it works
This is the stick.
Unfortunately (maybe) the Ministry view is that it is not in the business of driving a contractor to the wall.
If it doesn't work you can, to a point, tell the contractor to fix it. If the problem becomes really large then the contractor can go in to administration or the Ministry has to stump up more cash, usually under the guise of a contract variation.