Hi there,
The Fair Work Commission reviews EAs and Greenfield Agreements before they come into operation to make sure they don't contain any unlawful content.
Usually employees cannot be stood down unless there is an event out of the employee's control and even then it is temporary. The sort of events I am referring to are unforeseen and unpreventable equipment break down, industrial action and natural disasters.
However, you should start by reading the Greenfield Agreement to see what it says about stand downs and demotions because that will be your source of rights.