China's southwestern province Sichuan began limiting electricity supply to homes, offices and malls today due to a severe power crunch driven by extreme heat waves and drought, according to state media and one power company.

Residential areas, offices and shopping malls in Dazhou, a city of 5.4 million people, were informed of rotating brownouts each lasting several hours throughout yesterday, according to the official Wechat account of state-run Dazhou Power Group.

Residential brownouts are rare as China typically limits power supply to industries first to prioritise residential and commercial use in any power squeeze.

In what appears to be an official call to conserve electricity use, government offices were asked to set air conditioners to no lower than 26 Celsius and use more staircases instead of lifts, the provincial government-run Sichuan Daily said in a front-page report today.

Fountains, light shows and commercial activities during the night hours are to be suspended, the paper said.

Sichuan, which relies on hydropower to generate 80% of its power, on Sunday ordered producers of lithium, fertilisers and other metals to shut plants or curb output amid the worst heatwave in 60 years.

Soaring temperatures and little rain this summer have reduced hydropower generation in the province of 83.75 million people, while also boosting power demand for air conditioning.

Analysts said if the heatwave persists the power crunch could spill over to eastern provinces like Zhejiang and Jiangsu which have relied partly on buying electricity from Sichuan.