Turkish Energy Minister Hilmi Guler will visit Iran at the start of October, a senior Energy Ministry official said Thursday, the Ihlas News Agency, or IHA, reported.
Guler was originally scheduled to visit Iran early September for negotiations over energy issues, but he hasn't gone to Tehran yet.
Turkey has signed preliminary deals with Iran for construction of a gas pipeline running through Turkey to sell Iranian and Turkmen gas to Europe, developing three phases of Iran's South Pars gas field and construction of several gas-fired and hydroelectric power plants in Iran and Turkey.
Turkish firms, led by state-run oil and gas company TPAO, is expected to invest around $6 billion in developing three phases of South Pars field and construction of the gas pipeline.
The two neighboring countries were expected to sign a final agreement on energy cooperation during Iranian President Mahmoud Ahmadinejad's visit to Turkey in mid-August, but the agreement wasn't signed.
The Turkish official said the main problem in the negotiations is the agreement on how the gas produced in South Pars field would be shared.
The official said Iran wants to sign a 'service agreement' with Turkey that envisages Turkey extracting gas from the three South Pars phases and selling this gas to Iran.
However, Turkey prefers to sign a 'sharing production agreement' because it doesn't want to sell the gas to Iran and buy it again at a higher price.
Iran has refused the Turkish suggestion on the grounds that it violates its constitution.
The official said Turkey initially wants to provide cheap gas from Iran for its own needs, so it may accept Iran's 'service agreement' model but only if Tehran reduces the price of gas.