China raised its net diesel exports to the highest level in four years as domestic demand trailed output growth amid a slowing economy.

Overseas sales of the fuel in the world’s largest energy consumer exceeded imports by about 440,200 metric tons in June, according to data e-mailed by the General Administration of Customs in Beijing today. That’s the highest since May 2010.

“China is expected to export 300,000 to 400,000 tons of diesel a month regularly as domestic production grows faster than demand,” Chen Li, an analyst with ICIS-C1 Energy, said by phone from Guangzhou. China’s diesel demand is estimated to grow 0.3 percent to 1 percent this year, while output will expand about 1 percent, the Shanghai-based consultant said last month.

The nation may export a record 3 million tons of the fuel this year, exceeding the previous high of 2.87 million tons in 2010, ICIS-C1 said. China Petroleum & Chemical Corp.’s Tianjin refinery got a new diesel export quota this year, according to ICIS-C1.

China’s imports of fuel oil, used as refinery feedstock and to power ships, fell 31 percent from a year ago to 1.4 million tons in June, the second-lowest this year. Purchases in May were 1.13 million, the lowest since at least 2003. Imports declined 32 percent to 9.8 million tons in the first half.

The nation’s pipeline natural gas imports rose to a record high for a second month in June as supplies from Myanmar continued to increase, today’s data show. Imports were at 2.1 million tons last month.