Colleges and Universities Minister Glen Murray said the government is approving about 30,000 students a week for the program, but many students still don't know it's an option.
"You'd think everybody would know about this, this is the thing that's surprising me," Murray said Wednesday.
"We're going to be putting a lot more resources into raising the profile of the program, lots of students, we know, don't know about it."
That includes advertising through social media and having people on the ground so students can sign up on the spot.
"We have these street teams, we have sign-up booths in most of the colleges and universities right now where students are actually signing up for it and go right to a laptop, so that's working very well."
The program applies to more than 300,000 students, but excludes mature and part-time students, as well as those who are out of high school for more than four years. Students working on professional degrees like law and medicine are also excluded.
New Democrat Teresa Armstrong said the current program isn't fair because it pits students against each other instead of lowering tuition for all.
"The face of students certainly has changed and it's mature students with families who are struggling, people who are going to school part-time to try to better their careers," Armstrong said.
"Those students need a break. It's got to be affordable and accessible so all students can have that relief."
The Canadian Federation of Students has also urged an across-the-board tuition cut. Last month, it presented a 40,000-signature petition to the legislature asking that the $423-million annual cost of the rebate program be used to pay for a 13 per cent reduction in tuition fees for everyone.
The Progressive Conservatives, for their part, say a government facing a huge deficit should not be launching such an expensive program.
"We're all in favour of providing relief for families, but we also need to match that relief with restraining government spending," said Tory critic Rob Leone.
The government has said the program was deliberately designed to help students with their first four years of university.
Murray said cheques were already being sent out to the 160,000 students enrolled in the Ontario Student Assistance Program, who automatically qualify for the 30 per cent tuition rebates.
Close to 70,000 other students have applied online since the program began earlier this month, and those are now being processed.
The tuition program was a centrepiece of the Liberal campaign platform last fall and includes rebates of $730 for each college student and $1,600 for each university student from families with incomes under $160,000 a year.
The Liberals say five out of six families with students will benefit from the tuition rebates.