'Hopefully, during the next three months we will be able to conclude an equivalent figure,' Nematzadeh said, after referring to the $4,000 million signed over the past year for several refinery contracts. He said the contracts would involve foreign and domestic contractors.

Oil Minister Kazem Vaziri-Hamaneh said Iran would tap private and foreign investment to help meet the $15,000 million expansion of capacity. 'This will be an appropriate opportunity for co-operation between Iranian and foreign companies,' he said.

Iran has negotiated with companies from China, India and Malaysia to build refineries on a private basis, but none has yet been finalised. In November, Iran agreed to allow majority foreign ownership of refineries.

The shortage has been exacerbated by high subsidies, which make Iran's petrol some of the cheapest in the world at $0.09 a litre. The Majlis (parliament) is debating various proposals for increasing prices, instituting a dual-pricing mechanism for heavy users or more closely targeting subsidies to poor families.