In an interview broadcast Saturday by the Canadian Broadcasting Corp., Zhang Jungsai said a U.S. report accusing Chinese firms of industrial espionage included no real evidence of wrongdoing.
"I can assure you that our companies working in other countries are strictly doing business according to the local laws," Zhang said.
He added that anyone with evidence Chinese companies have stolen others' intellectual property should produce it. If they have no evidence, they should "shut up."
China National Offshore Oil Production Corp. has offered $15 billion ($14.98 billion U.S.) for Nexen Inc., based in Calgary. The proposed takeover, now under review by the Canadian government, is opposed by a majority of Canadians, polls show.
"We're here not to grab your resources. We're here to participate," Zhang said.
Canada's "transparent policies" make it an ideal country for Chinese firms to do business, he added.