The country's top work safety watchdog and China's health and labor ministries have jointly called for efforts to be stepped up to protect laborers on excessively hot days and ensure they are not forced to work in conditions that might expose them to heatstroke or accidents.

Construction workers swelter under the scorching sun at a construction site in Hefei, East China's Anhui province, July 3, 2011. [Xinhua]

"Complete and detailed measures should be laid out by governments at all levels according to local related laws and regulations," said an announcement made by the government departments.

Employers should provide necessary ventilation and cooling-off facilities at work when the mercury soars and offer workers drinks and medicine to prevent heatstroke, the announcement noted.

Enterprises should also reasonably adjust working schedules to ensure workers can avoid the worst of the hot days and must ease their workloads. And it said workers should qualify for subsidies if they have to work in environments where the temperature is above 35 C.

Work safety watchdogs' supervision and spot checks have also been urged to ensure laborers' rights are not abused.

But labor experts said such things are called for every year and noted that it would be better if they were enshrined in a specific law.

China's national law on sunstroke prevention, which mainly sets out ways to cool off in high temperatures at some specific workplaces, was brought in back in 1960 and has not been amended in five decades.

Yu Jiaxiu, a cleaner who has been working in plus-37 C temperatures for the past three days, said she had not heard that she might be entitled to financial subsidies because of the excessive heat.

Yu, 51, from Hubei, is working on cleaning up a section of a sewage-polluted river that runs through downtown Fuzhou in Fujian province.

She works from 7 am to 5 pm each day and is constantly exposed to the scorching sun.

"Our employers do not buy us drinking water and they don't provide us with an electric fan or sunstroke-preventing medicine," she said. "The hot weather and dazzling sunlight makes me sweat throughout the day and I sometimes feel faint."

She said that it would be hard to claim any subsidies for the hot weather because she does not even know the name of the company she works for, she only knows the name of the local contractor who employed her and who did not give her a contract of employment.

Each year, China registers many weather-related deaths among laborers. Last year, scorching heat claimed at least 40 lives in China. Most victims were street cleaners and migrant construction workers.

A heat wave is currently sweeping South China and meteorological authorities issued a warning on Monday about excessive and continued high temperatures in southern parts of the country for the next few days.

The mercury is set to hover between 35 and 37 C in most parts of South China and temperatures could edge up to between 38 and 39 C in some of those places, the National Meteorological Center said in a statement on its website.

Ye Jingyi, a labor law expert at Peking University, said there are some loopholes in the legal protection of workers, especially those who work outdoors.

Ye said the current law does not stipulate that workers can have a day off when the temperature reaches extremes. She said detailed clauses could be added to the law.

"It should clearly state which industries should suspend work if the temperature reaches a specific level and what kind of punishments employers will face if they violate the law," she said.

Heatstroke should also be listed as a potential workplace injury, she added.

He Li, a lawyer from the Yingke Law Firm in Beijing, said the law should also clearly state which subsidies will be paid to workers during extreme weather conditions.