BP has posted its first annual loss in almost two decades, a result of last year's devastating Gulf of Mexico oil spill, and raised the estimate of costs from the disaster to almost $US41 billion.

The company said it made a loss of $US4.9 billion last year, which was the first shortfall since 1992 and followed the worst environmental catastrophe in US history.

The loss compared with a profit of $US13.9 billion in 2009, while the costs estimate was lifted from previous guidance of $US40 billion, the company added in a results statement.

BP will, however, resume payment of its shareholder dividend at 7 cents per share.

The payout was suspended in the wake of the devastating spill in the face of intense US political pressure.

BP also said it would sell two major US refineries - including its Texas City facility which had suffered a deadly 2005 explosion that killed 15 workers and sparked safety concerns across its US operations.

Last year's Gulf oil disaster was triggered by a blast on the Deepwater Horizon rig - leased by BP and operated by Transocean Energy - that killed 11 workers.

The broken well was eventually plugged but not before it gushed about 4.9 million barrels of oil into the Gulf.

- AFP