(Adds comments from Tanaka, IEA's outlook on global impact from oil spill, background) By Mari Iwata Of DOW JONES NEWSWIRES FUKUI, Japan (Dow Jones)--The oil spill in the U.S. Gulf of Mexico may delay offshore oil development due to a U.S. government moratorium on new offshore drilling, as it is likely to take time to investigate the causes of the spill and develop appropriate safety requirements and procedures, Nobuo Tanaka, executive director of the International Energy Agency, said Friday. "There is little near-term impact. But for the medium term, if new offshore oil development in the U.S. is delayed by one or two years, the impact (on production) would be 100,000 barrels a day to 300,000 barrels a day by 2015," Tanaka told Dow Jones Newswires in the western Japanese city of Fukui, where he is staying to participate in an Asia Pacific Economic Cooperation group energy ministers' meeting. The Paris-based organization is now doing research on the possible impact on U.S. and global oil output by the moratorium. "If other countries like Angola, Brazil and the North Sea (countries) put on hold new offshore development and there is also one or two years of delay, the impact on global oil output might be 800,000 barrels a day to 900,000 barrels a day by 2015," said Tanaka. Although it would represent a mere 1% or so of global oil output, "given that spare oil production capacity is about 6 million barrels a day, (a reduction of) roughly 1 million barrels a day is unignorable," he added. Oil and gas companies began shutting down 33 deepwater exploration rigs last month after U.S. President Barack Obama imposed a six-month moratorium on developing new deepwater wells in the Gulf of Mexico. The APEC meeting will be held for three days starting Friday evening, where ministers and government officials will discuss energy security, sustainable development of energy resources and the adoption of renewable sources. -By Mari Iwata, Dow Jones Newswires; 813-6269-2798; [email protected] (END) Dow Jones Newswires June 18, 2010 02:32 ET (06:32 GMT)