While much of the country is busy combating deadly floods, the eastern region is suffering persistent heat that has prompted local governments to issue warnings about worker safety.

The municipal government of Shanghai issued a notice urging people working outdoors to take steps to avoid heatstroke, as the city and neighboring provinces have suffered extreme temperatures since last week.

Companies must adopt reasonable work schedules and shift lengths for their employees, increase breaks and reduce the intensity of labor during the hottest hours of the day to ensure workers' health, said the Shanghai notice, which was issued over the weekend.

The eastern metropolis has experienced high temperatures since July 20, with an average daily high temperature of 38 C. On Saturday, the high was 40 C.

Local meteorological authorities have forecast that the heat will continue in the region, with temperatures higher than 35 C for another week, possibly hitting 38 C on Wednesday and Thursday.

While many people can escape the heat by staying indoors with air conditioning, some workers are exposed to high temperatures to make a living.

Dong Zhizhong, a courier with e-commerce platform JD.com, said he starts work at 6 am and works without a break until 10 pm.

"We get paid by calculating the number of deliveries, so I don't take rests," said Dong, 41. "The company provides us with precautions against sunstroke and an 800 yuan ($120) allowance for the sizzling weather."

The sweltering heat has also led to record-high electricity consumption in Shanghai, where usage went beyond 30 million kilowatts on Monday.

"All the generators are working at full capacity, and the natural gas generators were warmed up and standing by in case of a further increase in power loads," said Wu Yingcong, head of the control center at Shanghai Municipal Electric Power Co.

In Nanjing, Jiangsu province, where the temperature hovered around 38 C on Monday following several scorching days, Lian Yongle, an air conditioner repair worker, said he worked until midnight on Sunday.

"People have to wait at least 24 hours before we're available. We work at least 12 hours a day and still cannot meet the demand," Lian said.

In Hangzhou, Zhejiang province, the urban management authority has urged road cleaners to take turns working when the temperature rises above 35 C. On days when the temperature exceeds 38 C, their work will be done by road cleaning vehicles instead.

Shi Xiaofeng in Hangzhou, Wang Yueyang in Shanghai and Xinhua News Agency contributed to this story.