MLAs are poised to investigate the weekly bill of £1.2m for substitute teachers.
The Assembly's Public Accounts Committee (PAC) will hold a hearing later this year on findings in a report just released by the Northern Ireland Audit Office.
The study revealed that the annual cost of stand-in teachers had soared by 40% over eight years to reach £66m in 2008/09.
It also revealed that education chiefs failed to reach a target of cutting sick leave to an average of six days per teacher per year.
The average sick leave in 2008/09 was 7.8 days, compared to five in English schools.
Veteran PAC member John Dallat said he expected the Committee to agree on a date for a hearing.
This will enable MLAs to quiz senior Departmental officials and then compile their own report.