Three Spanish ministers will begin an official visit to Iran on Sunday accompanied by a 70-member delegation which will include representatives of major businesses such as global energy company Repsol.
Foreign Minister Jose Manuel Garcia-Margallo, Industry, Energy and Tourism Minister Jose Manuel Soria and Public Works and Transport Minister Ana Maria Pastor Julian are to hold three days of talks with Iranian officials, Press TV reported.
The ministers will be accompanied by business owners operating in the fields of infrastructure, development and road building, as well as oil and gas.
Iran's oil exports were a regular fixture for Spanish refiners prior to sanctions in 2012. At one point, they accounted for 50 percent of Spain's oil purchases after the outbreak of Libyan political crisis.
Spain's CEPSA imported about 70,000 barrels per day (bpd) of oil from Iran, with Repsol taking in another 30,000 bpd before their imports were replaced with Saudi Arabian crude.
Repsol, Spain's largest oil company, also withdrew from a contract to develop phases 13 and 14 of the giant South Pars gas project in Iran with Royal Dutch Shell.
According to Iranian figures, trade in the year to March 20, 2015 stood at $321 million, whereas in 2011, the figure was €4.7 billion. Iran's energy exports constituted the bulk of the transactions.
Major European energy companies say they are looking forward to Iran returning to the market which absorbed 40 percent of the country's oil exports.
The recent conclusion of nuclear talks has triggered a race among the Europeans for new business opportunities in Iran. Ministers from Germany, France, Italy and the UK have visited Tehran with executives of major companies while further trips are on the cards.
Last week, the European Union said it was working on a political agreement to fast-track plans for future energy deals in Iran.
Financial data and news provider Bloomberg on Thursday cited 'two people with direct knowledge of the talks' as saying that the deal could be signed as early as November.
"The deal would cover five areas: oil and natural gas contracts, renewables and energy efficiency, power markets, energy infrastructure and direct investment in Iran's energy industry," it said.