Interest rates above 6 per cent are considered unsustainably high.
While New Zealand's IMF commitment is not earmarked for any particular part of the world, Finance Minister Bill English referred to Europe in his statement announcing the additional commitment.
"It's our expectation that Europe will continue to find solutions to its problems, but the IMF has a role in underpinning global certainty," he said.
A number of G20 countries had made additional IMF commitments in April, and more are expected at the meeting of the world's 20 largest economies in Los Cabos, Mexico, this week. The approach to New Zealand for additional commitments was made last week, English said.
"The new loan facility will be recorded as a contingent liability in the government's financial statements for the year to June 30 2012. However, it will have no impact on the government's track to surplus," he said.
As a small, open economy with high exposure to international trade and "one of the most indebted developed countries in the world", it was in New Zealand's interests to contribute to measures intended to produce a "stable, prosperous global economy."