The move by Saudi Arabia, Kuwait and Venezuela angered delegates and environmentalists at the conference in Buenos Aires that is trying to take forward last year's Kyoto agreement on climate change.
Ministers from more than 180 countries began a three-day negotiating session to draw up the rules under which the industrialised world can meet its various targets to reduce greenhouse gas emissions, and to find ways in which poorer, developing countries can be brought into the process.
America, the world's biggest emitter of the gases, wants to meet its target largely by buying up "pollution surpluses" from other countries. Poorer nations have said they will not join the process; the US has said it will not ratify the Kyoto treaty until the poorer countries give commitments of their own.
The Opec nations insisted that compensation planned for poorer nations for climate change impacts, such as sea level rise and droughts, should be widened to include their own potential loss of revenue.
In particular they sought their own share of a new green fund, the Clean Development Mechanism, which will enable rich countries to help poorer ones with energy-efficiency projects, and then take credit for the greenhouse gas emissions that have been saved.
Developing countries who might benefit from the fund were angered by the Opec move.
Edward Lowassa, Tanzania's environment and poverty alleviation minister, denounced it as "economic warfare".Reuse content