Rathika Sitsabaiesan, an ethnic Tamil, was subjected to "political intimidation" and warned of possible arrest and deportation, according to a statement on her New Democratic Party's (NDP) website.
"My experiences since arriving in Sri Lanka are a reminder that defending principles of human rights is not easy," she said in the statement, adding: "I was warned I could be subject to arrest and deportation".
The statement did not say who had intimidated her, but added that Sri Lankan authorities had informed the Canadian High Commission (embassy) in Colombo that there was no order to arrest her.
"We have not had anything to do with her, but I think she may be trying to get arrested hoping it will bring her more votes back in Canada," police spokesman Ajith Rohana told AFP.
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"We are not going to fall into that trap," he said.
Sitsabaiesan, 32, said she look forward to "learning more about the country of my birth".
There was no immediate comment from the Canadian High Commission.
Sri Lanka last week deported an Indian reporter on a charge of working in the island's former war zone without media credentials.
In November, immigration authorities detained two politicians from Australia and New Zealand while they were on a fact-finding mission into alleged human rights abuses during the island's separatist war.
Sri Lanka faces international censure over its failure to probe allegations that up to 40,000 civilians were killed by its troops in the final months of the battle with Tamil rebels in 2009, charges the country has denied.