A middle man may be necessary to facilitate crude oil deliveries from Iran to the international market, a national petroleum official said from Tehran.

Mohsen Qamsari, the director of international affairs at the National Iranian Oil Company, said independent Chinese refiners made purchase orders for around 2 million barrels of crude oil. They have the permits, he said, but "lack enough logistics and financial resources" to make further progress with Iranian transactions.

"We are now seeking a go-between for dealing with these refiners," he said.

Qamsari said that, so far, Dutch trader Trafigura was moving Iranian crude oil to the Chinese market. The director said talks are underway with the trader to move deeper into the Chinese market.

Trifigura would not comment on commercial transactions.

According to Deputy Petroleum Minister for International Affairs and Trading Amir Hossein Zamaninia, Iran expects to see signatures on the first new post-sanctions oil contracts before the end of the year. Characterizing the current status of the oil industry as satisfactory, the minister said Iran expects to bring in significant revenue from oil once new contracts unfold.

Iran in 2015 exported around 1.4 million barrels of oil per day, compared with an average of 2.6 million bpd in the era before sanctions were imposed in 2011. A multilateral nuclear agreement was verified in January, lifting some of the sanctions, and Iran said it's now exporting roughly 2 million bpd.

Royal Dutch Shell was among the first companies to buy Iranian crude oil in the post-sanctions era.