Heatwaves in northern and central China drove up electricity demand to record levels as millions switched on air conditioners to escape the sweltering conditions, while floodwaters in the south submerged villages and trapped city residents.

On Wednesday, China's meteorological administration issued orange alert warnings for high temperatures in regions across the provinces of Shandong, Henan and Hebei.

Several cities in Shandong, the second-most populous province, have issued "red alert" high temperature warnings, which have pushed up demand for air-conditioning among the region's more than 100 million people.

Temperatures in the regions were expected to hit above 40 Celsius this week, according to the state weather forecaster.

The maximum electricity load at Shandong's grid hit 92.94 million kilowatts on Tuesday, passing the 2020 peak of 90.22 million kilowatts, setting a new record, state television said on Wednesday.

Loads in adjacent Henan province reached a peak of 71.08 million kilowatts on Monday, exceeding the previous day's record of 65.34 million kilowatts, according to state media.

Premier Li Keqiang, visiting a thermal power company in the northern province of Hebei, said China must increase coal production capacity to "resolutely prevent power outages", according to a state media summary published late on Tuesday.

As heatwaves baked northern and central China, heavy rain has been falling in seven provinces in the south, including Guangdong, the country's most populous.

On Wednesday, 113 rivers in the mainland flooded above warning levels, with seven above historical levels, state television quoted the water resources ministry as saying.

In Guangdong, the provincial emergency management department said heavy rainfall has impacted 479,600 people, 27.13 hectares of crops and collapsed 1,729 houses, resulting in economic loss of 1.756 billion yuan, Xinhua news agency reported. (Reuters)