Venezuelan leader Hugo Chavez has called on oil-rich nations to dramatically reduce what they charge poor countries for the commodity.
Hugo Chavez believes Opec should have more of a "political" role
The poorest countries should only pay about $20 (£9.60) for a barrel of oil compared with current market prices of more than $90, Mr Chavez said.
Opec members should set aside $100bn from oil revenues to improve education and health in poor nations, he added.
Mr Chavez said he was seeking debate on what he said was "an explosive issue".
The Chavez government has used Venezuela's considerable oil wealth to fund social programmes at home and also to offer favourable terms of trade to countries in the region.
Critics have accused Venezuela of using oil to buy political influence around the world and of damaging its own industry by nationalising much of its key infrastructure and operations.
The Venezuelan leader said Opec members should discuss preferential pricing at their upcoming meeting in Saudi Arabia on Saturday, describing such a policy as a "marvellous mechanism of redistribution of the world's wealth".
"I would sell oil to a rich country at $100 and to a poor country perhaps at $20," he said.
"How are you going to sell oil to Haiti, one of the poorest countries in the world, at $100, the same price that you sell it to the US? It is not right ethically."
Mr Chavez said Opec needed to "raise its level of political action", while acknowledging that he expected to encounter "hard positions" on the issue among other countries.
The relentless rise in oil prices over the past couple of years has boosted the coffers of oil exporters while making life increasingly difficult for importing nations, many of which have had to heavily subsidise fuel prices to keep them down.
Oil prices neared $100 a barrel earlier this month but have since eased to below $92.