The journalists include Margaret Evans, Lily Martin and Jean-Francois Bisson, a videographer.
Ms Evans stated on her social media platform that they were arrested last week by Ugandan immigration officers and detained for 10 hours before being deported.
“#Ugandan gov’t [government] avoiding outside scrutiny of Jan[uary] elections already. We were deported Friday even though we had official media credentials,” she tweeted.
Mr Jacob Siminyu, spokesperson for the Ministry of Internal Affairs, yesterday declined to explain why the Canadian journalists were deported.
“Talk to the government spokesman about the details,” Mr Siminyu said.
Efforts to reach Mr Ofwono Opondo, the executive director of Uganda Media Centre, were unsuccessful.
However, Mr Opondo had tweeted in response to Ms Evans’ tweet that: “Do we really need you to scrutinise our electoral process to qualify as credible? Uganda reserves the right to admit foreign persons, including journalists. Good, stay where you are.”
President Yoweri Museveni and some government officials have been alleging that some foreigners are helping or favouring the Opposition for a regime change in Uganda.
Mr Museveni has repeatedly claimed that the National Unity Platform presidential candidate Robert Kyagulanyi, Bobi Wine, is being supported by foreigners.
He has not given evidence to prove his claim, which Bobi Wine has dismissed as a campaign gimmick.
Last month, the bureau chief of an international news agency was arrested and detained for days on allegations that he had assaulted a police officer in the 2016 General Election.
However, he was released after security agencies discovered that he had not come to cover news, but to visit his family.
In December last year, security agencies ordered international artiste Yvonne Chaka Chaka to leave the country moments before she performed at a Buganda Kingdom cultural event in Lubiri, Kampala.
Two heads of the United States and European Union funded non-governmental organisations in Uganda were deported in recent months on accusations of pursuing or supporting an agenda for regime change.
Mr Simon Osborn, who worked as country director of the National Democratic Institute, a United States-based organisation that promotes democracy across the world, was arrested and deported.
Mr Osborn had worked in Uganda for seven years.
Kenyan national Isaac Othieno, who had taken over as the acting head of the International Foundation for Electoral Systems, a US-based NGO that engages in advancement of democracy, was deported under unexplained circumstances.
Sources told the Daily Monitor that government had also barred “unwanted persons” from returning to Uganda.
Among those whose return has been blocked are Mr Marco Deswart, Ms Roseline Idele and Ms Lara Petrivevic. Mr Deswart, who heads election programmes at the Democratic Governance Facility (DGF), was reportedly barred from returning to Uganda in July.