UPDATE 1-China's H1 Iran oil imports drop, make case for waivers
* First-half imports at 424,183 bpd, down 1.9 pct on yr
* June imports down 39.1 pct on yr, 31 pct vs May
* First-half cuts on top of 21 pct cut in H1 2012
(Recasts to focus on H1 imports; adds quotes and details)
BEIJING, July 22 (Reuters) - China's daily crude oil imports from Iran fell 1.9 percent in the first half of the year from the same period in 2012, making it easier for it to stake a claim later to a waiver extension on U.S. sanctions against the Middle Eastern nation.
Countries that import Iranian oil must make steady reductions in their volumes to continue to receive six-month exemptions from the U.S. sanctions aimed at cutting off Iran's oil revenues and bringing it to the negotiating table.
China won a six-month waiver in June, along with other Asian importers of Iranian crude, and officials have said Chinese refiners would likely cut Iran shipments 5-10 percent this year from last. China's next waiver review is due November-December.
The drop in the first-half volumes came on top of a 21 percent cut in China's purchases from Tehran in the first half of last year. A contract dispute had slashed Iranian oil shipments in the first quarter of 2012.
June volumes imported from Iran were also sharply down compared with the same month last year and from May imports.
"It looks like China was getting a bit more aggressive with its cut in June in order to meet its overall target for the year," said Victor Shum, managing director of downstream energy consulting at IHS.
ChinaIran's largest oil client, brought in 424,183 barrels per day (bpd) of Iranian crude in the first six months of the year, data from the General Administration of Customs showed on Monday.
Compared with the second half of 2012, Chinese imports in the first six months of this year were down 4.6 percent, Reuters calculations based on customs data showed.
A Beijing-based trader dealing in Iranian oil said there would also be some cuts in Chinese firms' July loadings over contract volumes, which should be reflected in July-August customs data.
The main cuts for the year could come from Unipec, trading vehicle of Sinopec Corp, as the state refiner came under more political pressure compared to the unlisted state trader Zhuhai Zhenrong Corp, which was blacklisted by Washington in early 2012.
The U.S. and European measures aimed at Iran's oil exports have cost Tehran billions of dollars in lost revenue each month, although the volume reductions can fluctuate month to month.
Iran's top four buyers - China, India, Japan and South Korea - increased their purchases in May to 1.13 million bpd, up 11 percent from a year ago, according to Reuters calculations from earlier data and oil import figures.
That still puts Iran's oil exports down about 50 percent from pre-2012 levels.
South Korea also reported on Monday that its Iran oil imports were down 23 percent in June from the same month a year ago and down 27 percent in the first half of the year.
Washington has been seeking this year to cut Iran's oil shipments further, with some U.S. lawmakers saying the goal is Iranian crude exports of 500,000 bpd.
China imported 1.582 million tonnes or 384,980 bpd of Iranian crude in June, 31 percent below the import volumes in May, according to the GAC data.
The May imports from Iran had jumped nearly half from April because congestion at Chinese ports had delayed some of the tanker arrivals.
China's June oil import from Iran were down 39.1 percent from June 2012, when imports hit a then 11-month high of 633,000 bpd ahead of EU sanctions that banned insurers from covering shipment of Iranian oil.
China's total crude oil imports last month fell to the lowest in nine months at 5.39 million bpd, as a slowing economy cut into fuel demand by manufacturing and the transport sector.
June volumes from Saudi Arabia were down 20.7 percent on year for the month, according to the GAC data. The Saudi crude volumes were down 3.5 percent for the first half of the year.
To compensate for cuts in Iranian oil imports, China sharply increased purchases of Iraqi supplies, which grew 38.6 percent in the first half of the year over a year ago to 458,972 bpd.
(Addtional reporting by Florence Tan in Singapore; Editing by Tom Hogue)