TORONTO -- Grants that will make tuition free for thousands of students will increase along with tuition fee hikes, Ontario's colleges and universities minister said Tuesday as opposition parties clamoured for more details on the new program.

The Liberal government announced in its budget last week that it is combining existing programs to create an Ontario Student Grant, which would entirely pay for average college or university tuition for students from families with incomes of $50,000 or less.

Under the new program, half of students from families with incomes of $83,000 will qualify for non-repayable grants to cover their tuition and no student will receive less than they can currently receive.

The government is defining average college tuition as $2,768 and average university tuition as $6,160, for arts and science programs.

A cap on tuition hikes that had limited increases to an average of three per cent annually ends next year, as the grants are set to take effect.

"If the tuition fees go up, the grant goes up as well, so the grant is indexed to tuition fee increases," Training, Colleges and Universities Minister Reza Moridi said Tuesday.

The NDP is not convinced that will happen, since they said they had tried to get answers on it since the budget was released Thursday.

"We raised issues around whether or not this fund would be indexed to inflation, whether it would be indexed to tuition increases and those are questions that we have," said deputy leader Jagmeet Singh.

"The government now seems to be considering those and that's a positive sign but there is a lot of details that remain unanswered."

Once the three-per-cent cap expires in 2017, Moridi said there "maybe" will be a new once introduced.

"We will start working on that and we will make sure our students are not charged extra enormous amount of fees," he said. "So there will be government controlling the increase of tuition fees in university as we did in the past."

Premier Kathleen Wynne said the new program will cover average tuition for more than 150,000 students and make it more affordable for thousands more, granting money up front and allowing students to graduate with less debt.