The Tax Office could make workers pay their own uni fees if they fail.

A new proposal from Commissioner of Taxation Chris Jordan says ATO staff could be hit with the bill for their employer-sponsored uni courses if they get less than a credit.

That means even a low pass mark could see workers hit with the full price of a course they took to upskill at work.

The commissioner also wants to cap payments for the many ATO employees who take on extra study in accounting, business, economics, IT or law each year to just $500 per course.

The ATO says the proposed changes to the Tuition Assistance Program (TAP) are aimed at making the money last longer.

The education program was reviewed against “best practice in other organisations,” a Tax Office spokesperson said.

“Staff feedback indicated a need for greater scope and spread for the program.

“The ATO has not yet made a decision on changes to the program as we are committed to seeking input from a broad range of our staff to help inform our final decision,” the spokesperson said.

"Proposed changes include introducing a co-contribution scheme from 2017, which would see the ATO reimburse approved staff a set amount for each successfully completed course or qualification under the approved course of study," the spokesperson said.

“This approach would see the ATO's annual budget for financial assistance spread across a larger number of recipients.

“We are reviewing feedback received from staff on the proposed changes.

“Responses received over the last two weeks indicate the majority of staff support the proposal for a co-contribution scheme and welcome the broadened suggested course list.”

The Australian Services Union (ASU) sees it differently.

“Commissioner Jordan wants to destroy incentives for tertiary studies,” ASU official Jeff Lapidos wrote in a bulletin to members.

“The Commissioner's decision is likely to deter some ATO employees from pursuing tertiary studies, especially those who are having difficulty balancing their household budget and need the reimbursement to keep on top of their finances through the course.”

The union says the changes to the education scheme will come up in negotiations over the ATO's new enterprise agreement.