The head of the International Monetary Fund on Tuesday defended plans to create a 100 billion dollar fund to help countries mitigate the effects of climate change.

"The problem of climate change itself is not really in the mandate of the IMF," Dominique Strauss-Kahn told a group of students in South Africa's economic hub Johannesburg.

"What is in the mandate of the IMF is to help financing, in a sustainable way, what has to be done -- especially in the developing countries -- to deal with it."

Climate change "has a lot of macro-economic consequences", he said, including "consequences on the social security, a threat to democracy and sometimes a threat to peace."

"This is why the Fund has undertaken a mechanism sophisticated enough and innovative enough to allow the unblocking of the considerable sums necessary to deal with questions of climate change," he said.

The late January announcement of the "Green Fund" had raised worries that the Strauss-Kahn was trying to extend the IMF's mandate beyond its traditional sphere.

He said the IMF would in about two weeks release a working document to explain the proposed scheme.

The document will be sent for discussion by a high-level climate advisory panel set up by UN Secretary General Ban Ki-moon in mid-February.