Justin Trudeau says he's not just concerned about possible cuts Premier Doug Ford could make to Ontario's education system as Canada's prime minister — he's also concerned as a father with children in the province's schools.

Trudeau made the comments during a wide-ranging town hall meeting Thursday night at a Milton, Ont., high school.

The prime minister said he was "deeply concerned" about comments Ford made Wednesday, refusing to rule out cuts to all-day kindergarten and potentially growing class sizes in the province.

Trudeau told the crowd that cuts to education won't help the economy grow or provide opportunity for Canadians. But the cuts would also hit home on a personal level, he added.

Trudeau urges Ontarians to send message to Ford government

"I'm also a parent who has three kids in the Ontario public school system," he said, adding the potential cuts "worry me as a parent who's got his youngest kid in all-day kindergarten right now."

Ford said Wednesday that he isn't guaranteeing that full-day kindergarten will continue beyond the next school year.

The program was introduced by former Liberal premier Dalton McGuinty and was fully rolled out in 2014. It saves families thousands of dollars a year in child-care costs, but it costs the province $1.5-billion a year, at a time when the government is grappling with what it says is a $14.5 billion deficit.

Ford's government is conducting education consultations, including about the possibility of removing class size caps for kindergarten and primary grades.

Trudeau urged people to send a message to the Ford government.

"I'm hoping that Ontarians ... will make very, very clear that it would be a very bad political choice to cut opportunities for students and to cut education budgets," he said.

Says GM plant closure a 'shock'

Trudeau took questions from a crowd in the high school's gymnasium while others watched from an overflow room nearby.

Trudeau's office said approximately 1,300 people attended the 90-minute event, which was the latest in a series of

question-and-answer sessions held across the country.

The prime minister faced queries on a variety of subjects, including his environmental policy, immigration and political unrest in Venezuela.

Trudeau was asked twice what the federal government is doing to protect the jobs of autoworkers in Oshawa after General Motors announced it was closing its assembly plant there at the end of the year.

Trudeau said the news came as a "shock and a disappointment," and the federal government will continue to fight for the jobs.

"We are also working with the unions and other potential investors and automakers to look at what a future could be for that particular plant," he said.

Campaigning with Olympic medallist Milton candidate

Adam van Koeverden, the Liberal candidate for Milton, greets people before Trudeau's town hall event. (Cole Burston/Canadian Press) The Greater Toronto Area is expected to be a key battleground in the fall federal election. Earlier Thursday afternoon, Trudeau campaigned with the party's Milton candidate, former Olympic kayaking gold medallist Adam van Koeverden.

The pair surprised commuters at a transit station in the suburb west of Toronto, posing for pictures and chatting with people as they got off a train.

Van Koeverden, a star candidate for the Liberals, will face Conservative deputy leader Lisa Raitt, the popular incumbent in the Milton riding.