* Dec Iran imports 507,707 bpd, 4th highest in 2013
* China's daily Iranian crude imports in 2013 down 2.2 pct y/y
* Saudi imports flat; Iraq up 50 pct; Oman up 30 pct (Adds Oman's surge in ranking in last two paras, link to graphic)
By Chen Aizhu and Judy Hua
BEIJING, Jan 21 China's daily Iranian crude oil imports fell 2.2 percent to 428,840 barrels per day in 2013, a smaller-than-expected drop than previously forecast due to imports of condensate by an independent firm.
The annual cut, though less than expected, is unlikely to have repercussions for China over U.S. sanctions and comes as Washington and the European Union suspended some restrictions after a November deal over Tehran's nuclear programme.
The U.S. State Department has already extended a six-month sanctions' waiver to China for cutting Iranian oil purchases earlier in 2013, although Washington has said it will still aggressively enforce existing sanctions.
Tuesday's customs data showed that China's December crude imports from Iran fell 14.5 percent from a year earlier to 507,707 bpd.
For the whole of 2013, China - Tehran's top oil client and trading partner - imported 21.442 million tonnes of Iranian crude, or 428,840 bpd, data from the General Administration of Customs showed.
That compared with around 27.76 million tonnes, or an average of 555,200 bpd in 2011, prior to the latest rounds of toughened sanctions.
December's was down 5.7 percent versus November and the fourth highest daily rate last year, supporting indications that top refiner Sinopec Corp had increased liftings since November to top up cuts in previous months.
The cut for the whole of last year was below the 5-10 percent estimated by Chinese oil officials in late 2012, after independently-run petrochemical firm, Dragon Aromatics, had since the second half of 2013 shipped in Iran condensate, a light crude oil as feedstock.
A breakthrough agreement in November between Tehran and world powers allows the OPEC member to keep exports at the current reduced levels of about 1 million bpd, less than half the pre-sanctions level.
The deal also exempts buyers of Iranian oil, most of whom are based in Asia, from continually reducing purchases to earn a six-monthly waiver granted by the United States from sanctions.
For 2014, China may buy more Iranian oil as state-run trader Zhuhai Zhenrong Corp is negotiating a condensate contract that could raise imports to levels unseen since tough Western sanctions were imposed in 2012, Reuters has reported.
Total crude oil imports into China, the world's largest buyer after the United States, rose 4 percent last year, or by 216,880 bpd, more than a third slower than the 340,000-bpd increase in 2012, in line with moderating economic growth.
Iran was the sixth largest crude supplier to China in 2013, dropping from the previous year's fourth position as it was overtaken by Iraq and Oman, each marking an annual growth of 50 percent and 30 percent, respectively.
Saudi Arabia, the world's top crude exporter, exported 53.9 million tonnes (1.08 million bpd) to China in 2013, barely changed from 2012.
Iraq recorded the biggest incremental supply of nearly 160,000 bpd through December, or 50 percent, data showed.
Oman rose to rank the third largest supplier to China, surpassing Iraq, up from No.7 in 2012.
That is partly because China bought Oman's entire exports in July - of 3.3 million tonnes - to take advantage of attractive pricing and also to cover sharp cuts in Iranian and Kuwaiti imports in June and July, traders said on Tuesday.
(1 Tonne=7.3 barrels) (Additional reporting by Florence Tan in Singapore; Editing by Ed Davies and Himani Sarkar)