The National Iranian Gas Company (NIGC) and Saderat Bank of Iran signed a contract worth $4 billion to build two refineries.
Saderat Bank has 80 percent of the shares and NIGC the rest of the Bidboland 2 and Parsian Phase 3 refineries.
Bidboland 2 refinery is 17 percent completed and is scheduled to come on stream in 44 months.
Upon completion the refinery will produce 57 million cubic meters of natural gas daily, 1.48 million tons of ethane feed for Gachsaran Petrochemical plant, 1.51 million tons of liquid gas and 400,000 tons of gas liquids for export.
With the completion of phase 3 of Parsian refinery 1.3 million tons of ethane, 632,000 tons of propane and 481,000 tons of butane will be produced in the plant.
Meanwhile, Reuters reported that Iranian Oil Minister Massoud Mirkazemi stated, "A new relation has been established between domestic banks as investors and energy projects, which will lead to increase in efficiency."
The Islamic Republic says it needs around $25 billion a year in investment to meet its target development goal in oil and gas sectors.
"Western countries started imposing sanctions on Iran with the aim of deterring investment ... but signing such deals (with local investors) shows that development of our energy sector will speed up," Mirkazemi said.
"With the replacement of foreign firms with local companies, we have had good progress in our projects," he added.
Iran also says it is still drawing interest from Indian, Chinese and other Asian firms eager to enhance economic ties with Iran.
Iran boasts the world's second-largest natural gas reserves after Russia.
Iran exports gas to Turkey and Armenia and plans to export to Pakistan and the United Arab Emirates are in the pipeline.