"In advance of the G8 summit, I'm pleased to announce that Canada will establish new, mandatory reporting standards for payments made to foreign and domestic governments by Canadian extractive companies," Harper said.
"With 70 per cent of the world's mining companies listed in Canada, and 70 per cent of the world's free-enterprise oil located in Canada, our participation will help transform the way industry reports payments worldwide."
Leaders of the world's eight richest countries pledged after their 2011 meeting in Deauville, France, to consider new rules that would allow for greater scrutiny of companies' payments to governments. Critics say such measures are badly needed to expose corruption in countries with an abundance of natural resource riches.
Other countries, such as the United States and Hong Kong, already have similar measures in place.
Canada is a major player in the extractive industry, with hundreds of companies operating thousands of projects around the world.
Half of the mining that takes place around the world is done by Canadian companies. Sixty per cent of all the world's mining and exploration companies and 35 per cent of all oil and gas companies are listed on Canadian exchanges.
Anthony Hodge, head of the International Council on Mining and Metals, an industry group that represents some of the biggest mining companies, said the rules are needed both inside and outside Canada.
"This is not limited to out of Canada. There are issues inside Canada that are a real concern on this," Hodge said.
"But the issue is when you find yourself in a culture different than a Canadian culture where that kind of activity may be more common practice. And that's tough to deal (with) when you're a Canadian company trying to understand that culture and trying to bring to the table a less corrupt approach to doing business."
Oxfam Canada welcomed Harper's announcement, saying such transparency is vital if citizens in developing countries are to hold their governments accountable for investing resources revenues to fight poverty.
"We are very pleased that Prime Minister Harper has committed Canada to require extractive companies to report on their payments to governments," Mark Fried, the aid agency's policy director, said in a statement.
"We urge the federal government to work quickly with the provinces to ensure that the information is readily available to citizens in Africa, Latin America and Asia."
While there are already some standards and mechanisms in place for companies, these new rules would be enforceable by law.
"Now, obviously, this regime has been subject and will be subject going forward to additional consultations within Canada, but this is a direction we're determined to pursue because this information is essential for citizens to hold their governments accountable," Harper said.
"We'll obviously be working closely with the partners in the developing world."
The federal government will now consult with the provinces and territories, First Nations and aboriginal groups, industry and civil society organizations as it sets up its reporting regime. A senior Canadian government official, speaking on the condition his name not be used, said he expects it will take about two years to hold consultations and develop a framework for the new reporting regime.
Details such as how the reporting regime would be policed, and by whom, along with potential penalties for any companies that do not report their payments to other countries, need to be ironed out. It's possible provincial securities regulators could play a role, the official said.
The government is also trying to avoid burdening companies with too much extra paperwork, he added.
Transparency is at the top of the agenda at the coming G8 summit in Northern Ireland. British Prime Minister David Cameron wants to leave the lakeside Lough Erne resort with an agreement on tougher transparency measures in hand.
"As you know, my trip here and around Europe this week is in advance of the G8 meetings next week. Prime Minister Cameron, as we know, has identified a number of priorities for the G8 this year, and one of those is transparency in the extractive sector, specifically in the mining and energy sectors," Harper said.
"This has long been a priority for Canada. We put great emphasis in Canada on corporate social responsibility, and through our various foreign-aid programs, we have assisted transparency in the extractive sector around the world."
But Cameron is reportedly encountering some resistance to a proposal that would force companies to reveal who actually owns them. Some might consider it somewhat embarrassing to the British prime minister, who is chairman of the G8 summit, if he fails to seal a deal on ownership-disclosure rules.
Beyond talks about the economy and financial issues, the G8 is also expected to focus on international security, particularly the Syrian conflict, Iran and North Korea's nuclear programs and anti-terrorism measures in Africa's Sahel region.
The G8 summit comes as Canada and the European Union are trying to conclude lengthy negotiations on a free trade agreement. The Prime Minister's Office has sought to play down any expectations a deal will be announced while Harper is in Europe this week, saying an agreement at this juncture is unlikely.
Harper himself said Wednesday he doesn't want to put a deadline on the talks.
"Obviously, these have been long discussions. They're continuing. We have been making a lot of progress, and they are the biggest trade negotiations Canada has ever had in its history," the prime minister said.
"That said, we are not going to set a timeline or a fixed date on which we're going to have an agreement, because it is essential that we be driven by the contents of the discussions.
"We will not arrive at an accord until such time as we think we have the best accord we can get for the Canadian people. And that will be what drives us, the contents, not some artificial timeline."
Canada is under pressure to conclude a deal before the European Union turns its attention to free trade negotiations with the United States this summer.
Among the issues believed to be on the negotiating table are financial services, Canadian beef exports, country-of-origin rules for vehicles, procurement limits for provinces and municipalities and drug patent protection.
Meanwhile, sources tell The Canadian Press the Conservative government has agreed to smooth the way for more takeovers of Canadian companies by European firms in one of several concessions during free trade talks.
Canada has also agreed to open up parts of its hydro-electric sector to a limited amount of foreign investment, say sources in Canada with intimate knowledge of the talks.
Canadian negotiators have also agreed to a provision to raise the threshold for reviewing foreign acquisitions from Europe to $1.5 billion, sources say. All acquisitions under that value would not be subject to a government assessment about whether they create a net benefit for Canada.
Also on HuffPost