Canada’s Liberal government will introduce legislation to decriminalise and regulate recreational marijuana in spring 2017, according to the health minister, Jane Philpott.

The prime minister, Justin Trudeau, promised during last year’s election campaign that his government would legalise recreational marijuana, following the US states of Washington and Colorado, but the time frame has been unclear.

Philpott, speaking on Wednesday at a special session of the UN general assembly in New York on drug problems around the world, said the Canadian law will ensure marijuana is kept away from children and will keep criminals from profiting from its sale.

“We will work with law enforcement partners to encourage appropriate and proportionate criminal justice measures,” she said. “We know it is impossible to arrest our way out of this problem.“