BEIJING - China will set a minimum inventory level for commercial crude oil to keep the domestic oil market stable, according to the country's top economic planner on Wednesday.

All crude oil refineries must keep their crude oil inventories above 15 days' average processing level, and no less than 10 days' deposits if international crude oil prices exceed $130 per barrel, according to a guideline issued by the National Development and Reform Commission (NDRC).

Refineries should meet the minimum inventory level within a year, while the deadline for enterprises with limited stock capacity is three years, according to the guideline.

The new rule aims to address short term crude oil shortages and brace against international market fluctuation. Commercial crude oil reserves will be held in case of natural disasters or emergencies, it said.

China's commercial crude oil stocks were down 3.89 percent at the end of December from a month before, while stocks of refined oil products dropped 4.02 percent.