Edith Blais, 34, and Luca Tacchetto, 30, were last heard from on 15 December in the city of Bobo-Dioulasso.

The pair were travelling in Western Africa and were making their way to Togo for a humanitarian project.

Canada has travel advisories for Burkina Faso, due to terrorism and kidnapping.

"We're really worried because… the communications stopped abruptly and every kind of activity, every trace just completely vanished," Ms Blais' sister, Melanie Blais, told CTV News.

"They weren't worried about anything. They were having a really happy trip. She has been dreaming about travelling to Africa for all of her life."

A Facebook group set up by friends and family of Ms Blais says the couple were heading to Ouagadougou to sell their car, but never made it to the Togo border crossing or applied for visas.

The Canadian government has a travel advisory warning against all travel in Burkina Faso along the Togo border because of threats of "banditry and terrorism".

Radio-Canada reported that the Canadian government is treating their disappearance as a kidnapping, although the kidnapping has not been confirmed.

Global Affairs Canada told the CBC it is treating Blais's case as "extremely high priority."