According to the General Administration of Customs, China witnessed an astonishing 83.2-percent year-on-year slump in crude exports in March.

Crude oil imports last month, on the other hand, reached 13.9 million tons, up 8.8 percent year-on-year.

The trade pattern is set to continue for the rest of the year, said Han Xuegong, a senior consultant with China National Petroleum Company (CNPC).

"Although international crude price fluctuates at a fairly high level, the cost of production within China is also increasing with labor cost and raw material expenses on the rise. More importantly, the ever-soaring local demand for fuel requires less exports from the country. That's fundamentally why crude exports are nosediving," Han said.

Crude exports last month were only 218,988 tons. February exports were zero while January's stood at 300,000 tons.

Echoing Han, Cao Xiaoxi, chief engineer of Sinopec's Economic and Development Research Institute, predicted that crude exports are set to fall this year because of the consistent national trade policies discouraging the exports of crude and oil products.

China imposed temporary tariffs on 110 export items and cut tariffs on 58 imported goods late last year. Crude was on both lists. Crude exports carry a tariff of 5 percent.

"It's a long-term, clear policy to rein in crude and oil product exports. It's in line with the national interest," Cao said.

Niu Li, an economist with the State Information Center affiliated to China's top economic planner, the National Development and Reform Commission, said while exports will fall, rising local demand won't necessarily trigger more imports.

"There's no guarantee that oil imports will rise this year. It depends on international oil prices and the actual local demand," the energy expert said. High global oil prices will increase energy efficiency and promote energy conservation awareness, Niu said.

Oil imports may rise 10 percent this year compared with 14 percent in 2006 as government policies to boost energy conservation brings down fuel consumption.