Trudeau, speaking on French-language talk show "Tout Le Monde En Parle" -- recorded Thursday, before Riyadh confirmed Khashoggi's death at its Istanbul consulate -- insisted Canada would "always defend human rights, including with Saudi Arabia."
Canadian military equipment sales regulations contain restrictions on human rights violations against the buying country's citizens, and prohibit use against civilians.
Asked about a key deal with Riyadh for the sale of light armored vehicles worth CAD$15 billion, Trudeau said "in this contract, there are clauses that must be followed in relation to the use of what is sold to them."
"If they do not follow these clauses, we will definitely cancel the contract," he said, AFP reported.
Last year, Ottawa already expressed concern about the vehicles possibly being used in law enforcement operations in Saudi Arabia's east.
Canadian Foreign Minister Chrystia Freeland on Saturday branded Saudi Arabia's explanations as not credible and demanded a thorough investigation.
Relations between Canada and Saudi Arabia have been tense in recent months.
After Canada criticized the Saudi arrest of human rights activists, the kingdom retaliated by expelling the Canadian ambassador, recalling its own envoy to Ottawa and freezing trade and investment between the two countries.
On Sunday, German Chancellor Angela Merkel said her country would not export arms to Saudi Arabia amid the uncertainty around Khashoggi's death.