Speaking to a meeting of Caribbean leaders in the Bahamian capital Nassau, he said the ships will "conduct surveillance, gather intelligence and maintain a maritime presence off the Haitian coast in the coming weeks."

At a news conference later, he said the frigates would "assist the Haitian National Police in their efforts to control gang activity."

He also said that their mere presence in Port-au-Prince Bay would likely dissuade gangs from using the waterway for criminal activities.

Haiti, the poorest country in the western hemisphere, has been mired for years in a vicious cycle of humanitarian, economic and political crises exacerbated by brutal gang violence.

Last Friday, the United Nation's top human rights official Volker Turk called for an international force to be deployed to Haiti to help end this "living nightmare."

Trudeau said after a meeting with Haitian Prime Minister Ariel Henry that Canada "is very concerned about the ongoing unrest and instability in Haiti."

"Right now Haiti is confronted with unrelenting gang violence, political turmoil and corruption. Armed groups are committing murder, rape and other gender-based violence, kidnapping innocent people and recruiting children to terrorize and subjugate people," he said.

Speaking to reporters, he blamed much of the instability on "a small number of powerful elite families who are fomenting instability and financing violence for their own gains at a terrible cost to the Haitian people."

He said Canada is working with allies to increase sanctions on them, adding "that until the Haitian elites and leadership are held to account for their role in this horrific crisis in Haiti, we will not be able to deal with it."

Canada has imposed sanctions on former Haitian president Michel Martelly and two ex-prime ministers, as well as Haiti's only billionaire, Gilbert Bigio, and others.

On Thursday, Ottawa added more names to its sanctions list, and announced Can$12.3 million (US$9.1 million) in new humanitarian aid for Haiti as well as Can$10 million (US$7.4 million) for the International Organization for Migration to protect migrants in the region.

Canada's deployment of navy ships comes after patrol aircraft with reconnaissance capabilities were sent for a few days earlier this month to assist local authorities.