Iranian President Mahmoud Ahmadinejad is urging members of the Organisation of Petroleum Exporting Countries (Opec) to form a joint bank and stop pricing oil trades in US dollars.

According to the Iranian government’s Web site, Ahmadinejad told Opec Secretary General Abdalla Salem el-Badri the cartel should establish a joint bank as well as having joint currency.

Oil is priced in US dollars on the world market, and the currency’s depreciation has concerned producers because it has contributed to rising crude prices and eroded the value of their dollar reserves.

Iran has repeatedly urged Opec members to shift sales away from the US dollar. But Iran's proposal to trade oil in a basket of currencies is not supported by enough Opec members, which include staunch US allies such as leading producer Saudi Arabia.