China has received a new shipment of nearly 2 million barrels of Iranian oil in the past week, according to shipping trackers, with the cargo possibly destined for state reserves.

The 260,000 ton cargo, carried by vessel Dorena which is owned by the National Iranian Tanker Corp (NITC), was discharged at Zhanjiang port, according to shipping tracking specialist Vortexa Analytics as well as US advocacy group United Against Nuclear Iran, which specialises in tracking Iranian oil flows.

A Vortexa analyst told Reuters the cargo was for state reserves. Previous imports of Iranian oil for China's state reserves have also been facilitated by NITC vessels and discharged at Zhanjiang.

The cargo would be the fourth such shipment designated for state reserves since last December and is likely to be reported by Chinese customs which is due to release detailed commodities import data for June next month.

While China has been making sporadic official imports of Iranian oil, its private refineries over the past two years have also been buying large amounts of Iranian oil despite the United States' sanctions on the country's oil exports.

Some reports, however, said that unofficial Chinese imports of Iranian oil declined by as much as 50 percent in May as competition from cheap Russian oil increased.

Volumes of China's Iranian oil purchases, passed off as oil from suppliers such as Malaysia, Oman, Iraq or the United Arab Emirates, make up roughly 7% of China's total crude oil imports.

Most of these supplies were bought by Chinese independent refiners.

Reporting by Reuters