Canada will invite the leaders of a dozen additional countries to the Group of Seven summit in Charlevoix, Que., this month, as well as four international organizations, CBC News has learned.

Canada holds the G7 presidency for 2018 and will host the summit in Charlevoix June 8-9. Core members of the G7 are:

Canada.

France.

U.S.

U.K.

Germany.

Japan.

Italy.

Heads of the European Union.

It's become a tradition at G7 summits to invite countries beyond the core membership of the group. It allows the core members to expand their discussions beyond their own group of wealthy nations.

Often the invitees come from developing countries, though this year's crop of "outreach countries" includes one notable exception to that rule.

It's an unusually large group this year, twice the number that attended the G7 summit in Taormina, Sicily, last year.

It's also a geographically diverse group. Last year, all six invitees came from Africa. This year the outreach nations, which are chosen exclusively by the host country, come from every inhabited continent but Australasia.

The invitees are:

Argentina.

Bangladesh.

Haiti.

Jamaica.

Kenya.

Marshall Islands.

Norway.

Rwanda.

Senegal.

Seychelles.

South Africa.

Vietnam.

The heads of the United Nations, the International Monetary Fund, the Organization for Economic Co-operation and Development, and the World Bank are also on the guest list.

Argentina no surprise

One nation that comes as no surprise is Argentina, which this year holds the presidency of the G20. All of the members of the G7 are also in the G20.

Prime Minister Justin Trudeau visited Argentina in 2016 for talks with the country's President Mauricio Macri.

The two men had already established a rapport.

Prime Minister Justin Trudeau greets Argentina's President Mauricio Macri during a news conference at the government house in Buenos Aires in November 2016. (Natacha Pisarenko/Associated Press)

The centrist Macri came to office after defeating the leftist, pro-Chavez incumbent Cristina Fernandez de Kirchner the same month that Trudeau assumed office in Canada. Since Trudeau's visit to Argentina, they have met again on the sidelines of various summits, including the World Economic Forum in Davos, Switzerland, in January, and the Summit of the Americas in Lima, Peru, in April.

The two countries have sought to co-ordinate themes in their G7 and G20 presidencies, and Macri was expected in Canada, despite the fact that his country is currently dealing with one of its perennial economic crises.

Islands and coastlines

Rwanda is the only landlocked country on a list that includes several island nations.

Protection of the oceans and preservation of fisheries is a signature theme this year.

Some of the countries on the list (such as Argentina) have struggled to control illegal, unregulated fishing off their coasts by foreign vessels. That topic will be discussed in Quebec.

The Marshall Islands, Seychelles, and Bangladesh are all nations considered especially vulnerable to climate change and rising oceans.

Canada has invited Haiti, the poorest country in the Western Hemisphere, to the G7 summit of wealthy nations. Here, four children squeeze between two adults on a motorcycle as they commute to school in the Kenscoff Mountains near Port-au-Prince, Haiti, on May 29, 2018. (Dieu Nalio Chery/Associated Press)

Traditionally, developing nations are invited to outreach sessions, but Norway hardly fits that bill, enjoying one of the highest standards of living in the world.

But Norway is also a maritime nation that has been able to combine a strong offshore oil industry with a healthy fishery, which may help explain its presence on the list.

Haiti is the poorest nation in the Western Hemisphere and has suffered major environmental degradation. It is also the fourth-largest recipient of Canadian assistance, having climbed back after falling in favour, mostly because of its failure to hold successful elections.

A perhaps surprising absence is the country that was the No. 1 recipient of Canadian aid in 2015, Ukraine.

Canada has made significant efforts on behalf of Ukraine on the world stage.

After receiving substantial loans from Canada that year, Ukraine has fallen precipitously in Canada's foreign aid rankings, perhaps reflecting frustration with rampant corruption among the country's governing elite.