TORONTO - The Liberals are focusing on Ontario's children as they promise to boost mental health services in the province.

Premier Dalton McGuinty said Friday that his government would invest $257 million over the next three years to help 50,000 Ontario youth deal with mental health issues.

"I want these young people, I want their families to know, we're with them, all the way," McGuinty said as he stood at a construction site where a new treatment facility is being built for Toronto's Centre for Addiction and Mental Health.

"They'll get faster access to high quality services, more early identification and support and vulnerable children with unique needs will get additional help."

The Liberal plan would place mental health workers in schools and in the youth court system, add more short-term and crisis intervention in community agencies to cut wait lists and expand video-counselling services for children in remote areas.

The plan would also introduce "culturally appropriate" help for Aboriginal communities and would help youth transitioning between high school and post-secondary education.

McGuinty outlined his mental health platform in an emotionally charged speech where he quoted lines from two poems and shared an anecdote about his mother's time working in a psychiatric ward at a children's hospital.

"For generations, mental health issues had been misunderstood, stigmatized and concealed. Families too often felt alone and in many cases, helpless. Our world has changed," McGuinty said.

"Today we're more open, more understanding and more determined than ever before to help improve mental health for our people."

Statistics provided by the Centre for Addiction and Mental Health show half a million Canadians are absent from work due to psychiatric problems --a figure McGuinty said translated to about 200,000 people being affected in Ontario.

The centre also has figures which suggest 70 per cent of mental health problems begin during childhood or adolescence, but only one-third of those who need mental health services in Canada actually receive them.

McGuinty's mental health pledges were rolled out as his political rivals were gearing up for a leaders' debate on northern issues.

The Liberal leader has said scheduling issues prevented him from attending the debate in Thunder Bay and an alternate date was never provided.

"My friends, the need is great," he told mental health workers who had gathered to hear him speak. "We cannot allow families to lead their quiet lives of desperation, they're looking to us, they're looking to you."

McGuinty heads to Hamilton on Friday afternoon before travelling to Kitchener for a rally Friday evening.