Canada has finally ratified a foreign investment protection agreement with China after a two-year delay, a step that may help ease tensions between the two countries and smooth the way for a possible visit to China by Prime Minister Stephen Harper.

International Trade Minister Ed Fast announced the ratification on Friday and said the agreement, designed to give investors greater legal certainty, would take effect on Oct. 1. It was signed in September 2012.

Relations between Ottawa and Beijing have been strained by China's detention last month of Canadians Kevin and Julia Garratt on suspicion they stole state secrets and for threatening national security. The Garratts, who ran a coffee shop in Dandong on the border with North Korea, deny the charges.