The ministerial inquiry into the Novopay debacle will cost $500,000 and is expected to be completed by the end of May.
The details of the inquiry into the education payroll system was announced last week and more detail was released on Monday.
All aspects of the Novopay project will be investigated, from its outset to the present day.
Prime Minister John Key says that includes looking at what advice was given to the three government ministers who signed off on the project, despite being told there were problems with the system.
"There were two streams of that expert advice - the Novopay board and the four independent advisors that gave advice to the ministers overall."
The Inquiry will be headed by veteran public servant Sir Maarten Wevers and Deloitte New Zealand chairman Murray Jack.
The cost of the inquiry will come out of the ministry's budget.