Prime Minister Stephen Harper called on Parliament to pass Canada's free-trade agreement with Colombia, saying Wednesday it would "send a clear message" to Washington and around the world about the risks of protectionism.

Harper said statements by G-20 leaders have been encouraging, but Canada "will not be complacent" in the face of what he called "backsliding" by some G20 nations on free trade, including the United States.

He said Buy America sentiment growing in the U.S. Congress, as well as some states and municipalities south of the border, is of particular concern to Canada.

"It is the right thing to do for Canada, to do for Colombia, and the right thing to do for the global economy," he told reporters in Ottawa on Wednesday alongside Colombian President Alvaro Uribe.

"Forces of protectionism are always present, but they are even stronger and more dangerous at a time of global recession. Experience has shown us that a retreat to protectionism does not help the global economy. Rather, it makes things much worse."

Pact legitimizes Colombia's 'criminal regime': NDP

The free-trade pact was presented to Parliament in March after the two countries signed the pact last fall.

Since then, it has faced fierce resistance from some opposition parties over concerns about what critics have said is Colombia's dismal record on human rights, the Uribe government's alleged ties to right-wing paramilitary groups and its failure to protect murdered labour leaders.

The Bloc Quebecois and the NDP have vowed to oppose the deal, while the Liberals have not yet indicated whether they will support the Conservative government.

During Wednesday's question period in the House of Commons, New Democrat MP Peter Julian said approving the pact would mean Canada was "legitimizing a criminal regime" directly linked to "brutal military thugs."

Responding for the government, Gerald Keddy, parliamentary secretary to Trade Minister Stockwell Day, said the pact would enhance the human rights situation in Colombia much more than by keeping the country in isolation.

Keddy told the House that the NDP's opposition to free trade was based solely on "ideology."

But Julian fired back, replying: "Human rights is not an ideology; it’s a principle."