Asked to expound on a military official's statement that the choppers will be used for "internal security operations", Roque said they can always considering purchasing from other sellers.
Although he said he respects Canada's stand, Duterte said using the helicopters just to ferry troops and dead soldiers is "a insane proposition".
Canadian Prime Minister Justin Trudeau, during a talk at the University of Chicago Institute of Politics, said that the Canadian government is "in the process of looking" into the deal.
Mr Lorenzana said on Thursday that the helicopters will be used in a "limited" role primarily "for the transportation of personnel and supplies, ferrying wounded and injured soldiers, and the conduct of humanitarian and assistance and disaster response (HADR) operations".
News of the sale caused some in Canada to raise concerns over Duterte's human rights record.
The Canadian government initially defended the deal, saying the helicopters would only be used for disaster relief and search-and-rescue missions, and that the sale would support upwards of 1,000 jobs in the Montreal area.
Last year, Duterte earlier promised that he would purchase 23 armed helicopters to help them fight terrorists and other enemies of the state.More news: North Korea says USA is considering attacking them
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The Philippine defence department acquired eight of the same Bell aircraft model in 2015, which it said went mostly to an air force unit assigned with providing air transport for the Philippine president.
"The fact that Canadian equipment is making its way to the Philippine military raises serious questions about the effectiveness of Canada's exports controls-and about potential Canadian complicity, however unintended, in instances of human rights violation".
The Filipino military also uses derivations of the Bell-UH-1H helicopter, which first saw service for the USA military in the Vietnam War in the early 1960s.
Filipino officials have said the country would buy the aircraft from another source if Canada did not follow through on the deal.
But Trudeau's comment was not well accepted by Duterte.
Rights groups like Amnesty International have said the Philippine government's anti-drug campaign is causing a human rights crisis.