HAMILTON -- Ontario's New Democrat leader officially launched what her party is promising to be "the biggest campaign" in its history on Sunday, less than six weeks ahead of a provincial election.

At an event featuring community leaders, other legislators and Tom Wilson of Blackie and the Rodeo Kings, Andrea Horwath was nominated as a candidate in her riding of Hamilton Centre.

June's vote marks the third election in which Horwath has led the NDP.

Horwath released her party's fully costed platform earlier in April, promising free child care for families earning less than $40,000 and a boost to hospital budgets if elected.

She reiterated those promises at Sunday's launch, once again presenting the NDP as an alternative to the governing Liberals and the Opposition Progressive Conservatives.

She also reminded prospective voters of her promise to bring Hydro One back into public hands.

But the party has projected five consecutive deficits to pay for its plan, with a $3.3 billion shortfall in 2018-2019 falling to $1.9 billion by 2022-2023.