BEIJING: China has urged its big three energy producers to boost gas imports and output after an ongoing shortfall during an unusually early cold snap forced many cities to cut off supply to businesses.

China National Petroleum Corp (CNPC), Sinopec, and China National Offshore Oil Corp (CNOOC) have been called on to "actively arrange imports to increase natural gas supply".

The National Development and Reform Commission (NDRC), the top economic planning agency, also said they must "continue the heavy-load production and exploit (output) potential by every possible means".

The call was issued in a statement posted on its website Wednesday.

Northern, southwestern and eastern regions of China were struck by a supply crunch as low temperatures, rain and snow storms began to sweep swathes of the country from early November, the NDRC said.

Northern parts of the country saw demand rise as much as 56 percent this month from a year ago, while in Hunan and Hubei provinces consumption surged 22 percent.

Among the worst-hit cities, Wuhan in central China stopped supplying gas to 56 industrial and commercial users 11 days ago and refilling of the city's 8,300 gas-powered taxis resumed Wednesday after being cut for nine days.

Other cities including Hangzhou and Nanjing in the east and Chongqing in the southwest have limited or suspended supply to factories and entertainment venues to ensure household heating and cooking needs are met, state media reported.

The gas shortage has fuelled public anger over the monopoly of state-owned producers, accusing them of being reluctant to increase output in an attempt to jack up prices, the reports said.

To meet demand in the east and southeast, CNPC will import at least 700 million cubic metres (24.5 billion cubic feet) of liquefied natural gas from the spot market, the firm and government officials have said.

This was the first time it had imported the gas, the reports added.

CNPC, the country's biggest oil and gas producer, has said northern China was facing a supply shortage of eight million cubic metres per day and the south up to six million cubic metres daily, according to the reports.

The shortfall will be "hard to alleviate" in the near term even though gas output jumped by eight percent in the first 10 months of the year, the NDRC statement said.