The United Nations' new top advisor on food has urged a freeze on investment in bio-fuels in an effort to ease the global food crisis he said is deteriorating.

Olivier De Schutter, UN Special Rapporteur on the Right to Food, listed six avoidable causes for the rapid increase in food prices.

He said one is promoting biofuels like ethanol, which is made from plants such as corn.

"It is irresponsible to continue pursuing in such a blind fashion, our bio-energy policies. I believe that any new investment in first generation agro-fuels should be froze immediately and that we should discuss in an open and transparent manner, whether the current levels of production of bio-diesel, bio-ethanol, which are not so bio, should continue."

Other causes he mentioned included trade restrictions and speculative investing in commodities like wheat, soybean and corn which are driving up prices.

Last week, the UN Secretary-General Ban ki-Moon said its Food and Agriculture Organisation had developed a 1.7 billion dollar plan to provide seeds for farmers in the world's poorest countries. He also noted that the effort needs to focus on Africa, which could double food production over a very few years.