Yemen's 150,000 barrels per day Aden oil refinery resumed operations on Sunday after being shut for over a year as the conflict in the country worsened, an industry official at the refinery told Reuters.

"The refinery is back online and is refining 66,000 tonnes from the 1 million barrels it received from the Dabbah port it had in storage from before," the source said, adding the refinery was now operating at half of its processing capacity.

Power stations in the southern city of Aden have struggled to access fuel since exiled president Abd-Rabbu Mansour Hadi's forces drove the Iran-allied Houthi group out in July last year.

"Now the refinery can begin supplying to the power stations, and be used for other domestic purposes," the official added.

Yemen has been gripped by war pitting the Houthi group, backed by troops loyal to ex-President Ali Abdullah Saleh, and the internationally recognised Hadi government, which is backed by Saudi Arabia.

Hadi's government has regained control of large parts of the country's south and east in the past year.

Most foreign oil companies left the country after the war began in March 2015. - Reuters