Vehicle drama in ministry

Can the Prime Minister clarify if it is right for a minister to ask the department secretary to buy his vehicle?
This practice has been going on in some departments for a while.
What we know is that ministers are given, by Parliament, funds to purchase a vehicle to help carry out their duties.
If this is happening, then there is clear double-dipping by certain ministers.
There is a particular minister who has been pushing for his department to purchase his vehicle.
The same minister has been on quite a number of duty travels travelling with his secretary around the country and overseas at the expense of taxpayers.
This ministry needs to be investigated on how much as been spent for their “duty travels” that has not made any impact to the public.

Madang Matu