TRIPOLI  - Libya's state-run National Oil Corporation said on Friday its September revenues fell 11% month-on-month to $1.8 billion but were 9% higher year-on-year.

Its revenues came from sales of natural gas, crude oil, oil derivatives, taxes and royalties from concession contracts, it said in a statement.

The NOC said the decline in revenues was due to a rise in crude shipments late in the month, which meant the revenues would only be received in October.

"Our strategy to increase production and storage capacity is primarily to contribute to the stability of the oil market," NOC chief Mustafa Sanallah said according to the statement.

Sanallah also said that a new oil tank at Ras Lanuf port that opened in September had "increased the port's storage capacity by around 500,000 barrels of oil".

It "will alleviate future emergencies", he said.

Since the fall of long-time ruler Muammar Gaddafi in a 2011 NATO-backed uprising, OPEC member Libya has slipped into chaos and has had no proper budget as rival administrations vie for power.

(Reporting by Ahmed Elumami in Tripoli and Hesham Elsaba in Cairo; Writing by Yousef Saba and Ahmed Elumami; Editing by Edmund Blair and Jon Boyle) ((Yousef.Saba@thomsonreuters.com; +201222184730))