China's thermal coal futures hit record highs in early trade on Monday after four top utilities warned of potential heating and electricity shortages due to tightening supplies of coal and asked the government to help tame a months-long price rally.

At 9.30 a.m. (0130 GMT), the most-active futures were at 677.6 yuan per tonne, up 1.2 percent after rising as high as 679.6 yuan, the highest since the contract began in 2015.

Thermal coal futures have jumped over 10 percent this year, extending a months-long rally, as utilities scrambled for supplies to deal with soaring demand because of a cold snap that has swept across the north.

Last week, China'sState Power Investment Corp (SPIC), China Datang Corp, China Huaneng Group and China Huadian Corp asked the government in a letter to boost supplies of coal and temper the rally.

"The price rally is being driven by blizzard weather across the country, which has blocked highways and even rail transportation in some places and boosted demand for heating," said Xu Bo, analyst at Haitong Futures.

"It is hard to ease tight coal supply in a short period since China is currently at its peak period for heating," he added.

Xu said he expected coal prices to fall, although it may take some time, as prices were already above levels that the country's utilities could afford.