China said Wednesday coal reserves at some power plants had fallen to danger levels, and pledged to increase coal shipments to power plants to ensure adequate electricity supply during winter.

"Although coal shipments to power plants have increased since early this month, reserves in the key 349 power plants have dropped from 38 million tonnes mid-November to less than 35 million tonnes now," the Ministry of Railway (MOR) said in a statement.

"Reserves in some plants have dropped to the danger mark or even below it," it said.

The MOR vowed to put 2,614 more trains to use bringing the total daily loading to 43,100 trains for the rest this month, and at least 45,000 trains on average for December.

Local authorities should keep a close watch on coal reserves and consumption, it said.

During the summer and winter months when electricity demand peaks in China, ensuring coal supply to power plants can become problematic due to limited railway transportation capacity.

About 70 percent of the nation's electricity comes from coal-fired power stations.

This winter, the situation is likely to be complicated by surging coal prices as well as government measures to conserve energy and cut emissions.

Liu Zhenya, general manager of the State Grid Corp. of China (SGCC), said Tuesday that provinces in north China reported record high power consumption during the first half of this month.

Figures from the National Power Dispatch and Communication Center showed both power output and consumption increased on a monthly basis in the first half of this month, up 8.9 percent and 7 percent respectively on the same period last month.