Certainly action is needed in cases of wasteful and corrupt expenditure, but the general designation "unauthorised expenditure", while simplifying things for journalists seeking a headline, is woefully inadequate.
To make up a simplified example,  a municipal roads department has two budget items: one for repairing potholes, and a second for painting white lines down the middle of the road. Part way through the year, the pothole budget is exhausted, while the line-painting budget still has more than adequate funds.  Anyone diverting funds from one item to the other is committing an event of misgovernment, unless the action is sanctioned by innumerable officials, and blame is attributed for "unauthorised expenditure".  
It would seem that more clarity and detail in reporting is needed.