RIYADH, (Reuters) - Credit offered by Saudi Arabia's banks fell to its lowest level in at least 13 months in December and closed 2009 with a first annual drop since at least 2001, central bank data showed on Tuesday.

The global financial crisis froze credit in the Arab Gulf, the world's largest oil exporting region, last year and debt restructuring of Saudi family firms and Dubai's flagship conglomerate are expected to weigh on credit growth this year.

Bank credit in the Saudi kingdom stood at 736.9 billion riyals at the end of December, down from 752.8 billion in the previous month and 744.8 billion at the end of 2008, data from the Saudi Arabian Monetary Agency's (SAMA) website showed.

Banks claims on the private sector, a measure of banks' confidence in private sector growth prospects, stood at 734.2 billion riyals by the end of December, showing its first month-on-month drop in four months, the data showed.

The central bank's net foreign assets rose to 1.52 trillion riyals in December, their highest level since March, 2009. The assets stood at 1.46 trillion riyals in November, 2009 and 1.64 trillion in December, 2008.

Monthly credit data only stretch back 13 months.