TORONTO -- Cellphones will be banned in Ontario classrooms during instructional time, starting in September -- news that some suggest is meant to distract from ongoing criticism over autism funding.

Education Minister Lisa Thompson said in a statement Tuesday that a formal announcement is coming soon.

"Ontario's students need to be able to focus on their learning -- not their cellphones," she wrote. "By banning cellphone use that distracts from learning, we are helping students to focus on acquiring the foundational skills they need like reading, writing and math."

Some schools already have similar policies, but the province will issue a directive to all public schools for the 2019-20 school year, government sources told The Canadian Press. How to enforce the ban would be up to individual boards and schools.

Exceptions would be made for when teachers want to use cellphones as part of their lesson, for medical reasons and students with special needs.

Harvey Bischof, president of the Ontario Secondary School Teachers' Federation, said it doesn't sound like the policy will differ from what is already happening in schools.

"The notion that teachers are simply allowing inappropriate cellphone use at the moment is incorrect," he said.

"My suspicion is the only thing it's meant to change is the discussion that's going on around the return of kids on the autism spectrum to schools on April the 1st without the appropriate supports."

Thompson announced additional money for school boards and training for teachers Monday as hundreds of kids may soon enter school because they will get less funding for therapy. Changes the government is making to the Ontario Autism Program as of April 1 have come under fierce criticism from parents and advocates, who say kids now won't the levels of therapy they need.

NDP education critic Marit Stiles noted that a recent memo from the education ministry advised school boards to defer filling vacancies for retirements and other leaves for teachers and other staff until a promised update by March 15.

That could mean education cuts, larger class sizes or changes to full-day kindergarten, Stiles suggested.

"I think that this (announcement) has everything to do with a government that's trying to distract from the really serious and considerable concerns of families and education workers," she said.

The Green party questioned why a government focused on cutting red tape is introducing "a top-down regulation that complicates things for educators on the front line."

The Tory government conducted education consultations last year, and while input on the sex-education curriculum dominated headlines, feedback was also gathered on a potential classroom cellphone ban. About 97 per cent of respondents favoured some sort of restriction on phones in class.

"It was the closest thing we got in our consultation to unanimity," one source said.

The Progressive Conservatives had proposed such a ban in their platform during last year's election campaign.

The Ontario Public School Boards' Association did not provide comment Tuesday, but in its submission to the government consultations it had urged the province to continue allowing school boards to make their own decisions.

"Students need to be discerning digital citizens and opportunities should be provided within the curriculum to allow students to safely explore various uses and risks of technology in an intentionally guided and supportive environment," the association wrote.

"Schools and teachers have well-established limits and boundaries with regard to cellphone use in schools and the classroom, similar to other classroom expectations, which are designed to create positive learning environments."

The Toronto District School Board used to have a cellphone ban, but reversed it after four years to let teachers dictate what works best for their classrooms. The board has previously said that enforcing an outright ban was next to impossible, and said that to curb technology use would be to place limits on educational opportunities as well.

Spokesman Ryan Bird said the TDSB encourages appropriate uses of technology in classrooms.

"We leave cellphone use up to individual schools and classrooms to do what works best for them," he said.

A 2015 London School of Economics and Political Science paper found that "student performance in high stakes exams significantly increases" with a ban on mobile phones. The improvements were largely seen among the students who were normally the lowest achieving.