There are a number of ways to do it, whether it's through estimates, a discretionary fund up to a certain amount or high-level approval within the ministry. There'd be some stuff approved at this level and some stuff approved at that level. I think implementing a reporting requirement would quell some of the concerns about it. It could be put within discretionary funding or be subject to a judicial review if over a certain amount. There are any number of ways to make sure the minister is doing this properly, if they choose this.
Remember that it's not required. Again, it is at the discretion of the minister.