Oxfam Hong Kong on Monday called on the government to set new guidelines for sanitation workers so they can stop working during periods of extreme heat.

The NGO surveyed 200 sanitation workers from the Food and Environmental Hygiene Department between June and July. It found that over two-thirds had felt physically unwell at work, with some developing heat-related illnesses.

Oxfam found that the average temperature inside refuse collection points in July was 32.2 degrees Celsius, even higher than the record-breaking average temperature during the month, which was 30.3 degrees Celsius.

The government earlier announced that officials were working to update heat stroke prevention guidelines, including arrangements regarding rest breaks and work intervals.

Wong Shek-hung, Oxfam’s programme director for Hong Kong, Macau and Taiwan, said rest breaks alone would not be enough to protect workers in hot environments.

"The mainland also offers outdoor workers to have breaks or even stop working under extreme heat. It is a kind of occupational safety requirement. We urge the [Hong Kong] government to include this concern in their coming study," Wong said.

More than 30 percent of those interviewed said they worked in renovated or newly built refuse collection points, but Wong said the working environments were no better than those at older sites.

"The new ones may be more appealing to the public, but workers reported that the ventilation was not improved after the renovation. We think the government should improve this in the coming renovation exercises," she said.

Oxfam also called on the government to provide "high-temperature subsidies" for outdoor workers.