The major issue of oil dealings with Greece, which has four refineries, demonstrates the way in which trade in Europe could stop as a result of a breakdown in confidence due to the euro zone debt crisis.
"Companies like us cannot deal with them. There is a lot of risk. Maybe independent traders are more prepared for that," said a trader which has a major international oil company.
"Our finance department just refuses to work with them. Not that they didn't pay. It's really just a precaution," said another major trader.
"We couldn't find any bank willing to finance us. No bank wants to finance a deal for them. We missed some good opportunities there," said another trader. As a result of the insufficient bank financing, Greece had to stop purchasing crude oil from Russia, Azerbaijan and Kazakhstan.
Greece's primary oil refiner "Hellenic Petroleum" denied experiencing any difficulties in getting crude. Greece's second biggest refiner "Motor Oil Hellas" refused to make comment.
According to Reuters, more than seven ships with Iranian oil cargo reached Greece during the last 2 months and there are more to come.
EU announced a few days ago that it might take oil sanctions against Iran, right after a U.N. agency reported that Tehran is going to design nuclear bombs.