"Norway today offered the International Monetary Fund a loan of 55 billion kroner to help stabilise the European economy," Stoltenberg told reporters.
Earlier this week, the 17 countries that share the euro pledged €150 billion ($195 billion) in bilateral loans for the International Monetary Fund to assist the debt-laden eurozone.
European Union leaders had called at a December 9th summit for €200 billion, including contributions from non-eurozone countries.
"We are doing this because it is in our interest to restore enough order in the international economy to be able to get out of the crisis we are currently bogged down in," Stoltenberg said.
"It is not a gift, it is an investment," he insisted.
The loan requires approval from the Norwegian parliament and is conditional on other contributions from other countries, he said.
Four non-eurozone members of the EU — the Czech Republic, Denmark, Poland and Sweden — each pledged on Monday to make loans to the IMF for use in stabilising the eurozone.
But Britain, also a member of the EU but not of the eurozone, has meanwhile refused to stump up its roughly 30-billion share.
Norway is not a member of the EU but its economy is heavily dependent on exports to the region.
While the Norwegian economy remains robust thanks to its oil industry — it is the world's seventh-biggest exporter of black gold — the Scandinavian country is concerned about an economic slowdown in Europe that would lead to a reduction of its exports.