WA's Under Treasurer says the Education Department is yet to inform him how it will achieve almost $50 million in savings this financial year.

Tim Marney has appeared before a parliamentary committee that is taking a closer look at the Education Department's budget this year.

He says if the department is to meet its budget targets, it will need to find an additional $47 million in savings this year, and another $40 million the year after.

Mr Marney says the department has not told him what measures it will take, and if he does not hear back soon, he will have to write it up as as a risk in the mid year review, due in December.

He has also expressed concern about the department introducing a long service leave liability levy on individual schools to achieve $15 million in savings.

Mr Marney says he is not convinced the measure will solve the problem of teachers accruing excessive leave.

Members of the committee, on both sides of politics, have been highly critical of the Education Department's ability to manage its own budget throughout the hearing.