Prime Minister Stephen Harper issued an invitation Saturday for five more countries to join the G20 summit in Toronto next month, a meeting he said will focus on global economic recovery and the European debt crisis.

Harper, who wrapped up his week-long tour of Europe with a brief stop in Berlin, announced that the leaders of Ethiopia, Malawi, the Netherlands, Spain and Vietnam have been added to the G20 guest list.

"G20 leaders have important work to do when we meet in Toronto in June and participation by these countries will bring valuable perspective to that task," Harper said in a statement.

As host of the June 26 summit to be held in downtown Toronto, Harper gets to choose which additional nations get an invitation. Similar invites have gone out before previous summits.

Meanwhile, in a joint news conference with German Chancellor Angela Merkel, Harper said he was not fazed by this week's wild market fluctuations or the continuing Greek economic crisis.

"Markets bounce up and down and I'm confident that they will see rationality as we move forward," the prime minister said. "But I'm also confident that our European friends will take whatever measures are necessary to ensure that the situation moves forward in a positive direction."

But in his meetings with Merkel, Harper was told that a $140-billion European Union aid package for Greece that was supposed to stop that country's economic slide will not suffice.

Merkel says "the stability of the Eurozone as a whole is not guaranteed with this program alone."

EU countries agreed late Friday in Brussels to new measures to curb market speculation and to speed up joint action if more countries founder.

Harper said the G20, and the G8 summit which will precede it, will be focused almost entirely on economic issues on the theme of "recovery and new beginnings."

"The G20 will target the economy," he said. "There are signs of recovery in most of the economy (but) at the same time it's necessary to continue to work strongly and aggressively on reform of the financial sector."

Also attending the G20 summit will be the heads of the World Bank, the International Monetary Fund, the Financial Stability Board, the Organization for Economic Cooperation and Development and the United Nations, among others.

The G20 includes 19 countries -- Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, Republic of Korea, Turkey, United Kingdom, United States of America -- and the European Union.

The G20 accounts for 90 per cent of global economic output, 80 per cent of world trade and about two-thirds of the world's population.

Harper spent less than six hours in Berlin, meeting with the German Chancellor and visiting a cemetery for downed Second World War air crews at a ceremony with veterans.

The Canadian delegation also took part this week in moving liberation ceremonies in Holland.

Harper's stop in Berlin coincides with the 65th anniversary of Germany's unconditional surrender to end the Second World War, signed in Berlin on May 8, 1945.

With files from The Canadian Press