The committee added there had been 11 deaths on World Cup projects - "two work-related fatalities and nine non-work related deaths of workers".
It said migrant workers in other Gulf Cooperation Council (GCC) countries - Bahrain, Oman, Kuwait, Saudi Arabia and the United Arab Emirates - were also vulnerable as statutory summer work breaks were not linked to actual weather conditions.
Around two million migrant workers live in Qatar, outnumbering the local workforce by almost 20 to one.
But the US -based HRW remains concerned about a lack of detail in its statistics for worker deaths and the fact it does not take into account the effect of sunlight when setting heat-stress safety limits.
The Qatar government told CNN that the country constantly reviews its labour policies to ensure migrant workers have the "necessary on-site protections".
The current rules prohibit working outdoors between 11:30 a.m. and 3 p.m. from June 15 to August 31, when it is usually more than 40 degrees Celsius, but make no allowance for the actual heat or humidity, so it could still be over 40 degrees when work is allowed.
Qatar, a country with a negligible football background or infrastructure, was a controversial victor of the right to host the 2022 Fifa World Cup, which will be held in November and December to minimise the impact of the desert state's harsh climate.
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McGeehan added: "They should also be demanding answers to two simple questions - how many workers have died since 2012 and how they have died?"
"Qatari authorities should immediately replace the work ban limited to midday summer working hours with a legally binding requirement based on actual weather conditions consistent with global best practice standards", HRW have said. The SC has provided HRW with the information requested concerning the circumstances surrounding non-work related deaths on SC projects.
The SC explained that it does not have the authority or mandate to determine cause of death, which is reflected in death certificates issued by the medical authorities in Qatar.
The SC underlined that it investigates all fatalities on SC sites to establish whether they could have been prevented.
Before that, three Indians employed on World Cup sites died of heart attacks, according to a 2016 report by Qatar's World Cup organising body, the Supreme Committee for Legacy and Delivery.
A Federation Internationale de Football Association spokesperson said it was working closely with the Supreme Committee, adding that health and safety and workers' protection measures put in place by the committee met the "highest worldwide standards".
Breaking with tradition by starting in the Gulf state's much-cooler winter, the 2022 edition of the FIFA World Cup will take place from November 21 till December 18. But only the 12,000 World Cup workers - 1.5% of the country's construction workforce - benefit from this mandate.