Prime Minister Justin Trudeau said today the provincial Progressive Conservative government's cuts to Ontario's education system are "frightening" — and he worries they could undermine the quality of the education his three kids receive at an Ottawa-area public school.

Speaking at the Canadian Teachers' Federation's annual general meeting in Ottawa, Trudeau took aim at changes made by Premier Doug Ford to trim costs in Ontario's sprawling public education system, which has more than 2 million students enrolled on average each year.

Protests have followed the government's pledge to increase class sizes (average class size for grades four through eight will rise from 23.84 to 24.5, while grades nine through 12 will jump from 22 to 28), introduce mandatory e-learning modules and cut as many as 3,000 full-time teaching positions.

The Ford government says it hopes to eliminate those teaching jobs through retirements and attrition. According to the latest figures, there are roughly 126,000 teachers in Ontario.

"As we look at what the Conservative government in Ontario ... has done in terms of cuts to services, cuts to kids, it's really frightening," Trudeau said during a pre-election "armchair discussion" with the teachers advocacy group.

"As a federal politician, even as prime minister, I'm not supposed to have too much of an opinion on provincial education policy. But I was a teacher and I'm also a parent with kids in the system, and I'm very, very worried about them suddenly showing up in September with a class size of 30 plus, less support for the special needs kids, and an environment that is generally hostile to teachers," he said.

In Canada, education is an area of provincial jurisdiction.

Stephen Lecce, Ontario's education minister, said the prime minister was being unnecessarily divisive by going on the attack against the provincial government.

He said it's clear the prime minister would rather run an election campaign focused on Ford instead of speaking about the Liberal record in Ottawa over the last four years.

"On the eve of an election, it is regrettable that the prime minister is ill-prepared to put the national interest ahead of his own political interest. He's campaigning instead of leading the country," Lecce said in an interview with CBC News.

"What we need now more than ever is a prime minister with the political leadership to help unite the country and collaborate with the provinces to, yes, improve education and give people hope that they can obtain jobs so that they can compete in the global workplace."

Ontario Premier Doug Ford shakes hands with Stephen Lecce after he is sworn into his role as minister of education (Tijana Martin/The Canadian Press)

The minister said, under Trudeau's leadership, national youth unemployment rates are stubbornly high — consistently above 10 per cent for those aged 15 to 24 — even in an era of record low unemployment rates for other age cohorts. "We need to do better at all levels of government," he said.

Lecce, who assumed the position after Lisa Thompson was shuffled in Ford's June cabinet overhaul, said he is focused on improving Ontario's education system and educational outcomes by bolstering mental health investments and engaging in a major rewrite of an outdated curriculum. He said the government has so far injected some $700 million in new spending into the education system as part of these reforms.

The Ford government has said the current public education system is "broken" and is not producing acceptable test scores in some key subject areas, such as mathematics.

It has defended the cuts as necessary to help get the province's fiscal house in order after years of budget deficits that have left Ontario with the world's largest sub-sovereign debt levels.

Moreover, beyond the cuts, the Ford government has said it is intent on "modernizing" the school experience by focusing on disciplines like science, technology, engineering and mathematics (STEM), new online learning options, financial literacy, and support for students interested in skilled trades.

Prime Minister Justin Trudeau speaks with Don Peterson of B.C. and his daughter Gracyn after participating in a discussion at the Canadian Teachers Federation annual general meeting in Ottawa. (Adrian Wyld/Canadian Press)

Teacher groups have said the cuts are a devastating blow to an education system that is generally well-regarded internationally. The hike to classroom sizes will be particularly difficult to manage for teachers, the unions have said. Changes to the Local Priorities Funding program will mean a loss of some $235 million for special education programs to support children in need and at-risk students.

Trudeau's criticisms appear to be part of a Liberal federal election campaign strategy of running against the controversial Ford and his unpopular budget cuts — a tactic that was on display Thursday as Trudeau warned that electing federal Conservative Leader Andrew Scheer would lead to the introduction of Ford-like policies in Ottawa.

Trudeau said Conservatives can't be trusted when it comes to the education system, reminding the largely friendly audience of educators that the Conservative election campaign of 2015 ran attack ads mocking him for being a drama teacher who wasn't "ready" to lead.

"We saw the Conservatives try a number of attack lines on me that I was just a teacher, and how could I become prime minister. I mean the issue, and this is a personal thing, I think being a teacher informs deeply how I am prime minister," he said.