Halifax MP Linda Riordan has tabled a Parliamentary Early Day Motion, backed by seven other Labour MPs, urging the Government to resolve uncertainty for employers by introducing a maximum working temperature.
The MPs said any employee doing strenuous work should be allowed to stop working if temperatures reach 27C.
Even though there are health and safety regulations in place that state the temperature in the workplace should be at a "reasonable level", there is uncertainty as to the upper limit.
"Employees in a wide range of workplaces - from industrial bakeries to school classrooms - are often subjected to high temperatures which can impact seriously on their health and wellbeing, with effects ranging from discomfort, stress, irritability and headaches, to extra strain on the heart and lungs, dizziness and fainting, and heat cramps due to loss of water and salt," said the motion.
It also warned that overheating can lead to a "reduction in cognitive function, attention span and visual motor tracking which may cause accidents and fatalities".
The TUC has also urged employers to think about their employees when temperatures soar.
"Just when we thought summer had passed us by this year, the UK is now basking in sultry temperatures and the glorious summer weather set to continue for some time," said TUC general secretary Frances O'Grady.
"But any prolonged hot and sunny spell is not going to be fun if you're trapped inside an overheated workplace.
"As soon as the temperature starts to soar and begins to nudge 24C, employers should be allowing their staff to dress down for summer and making sure that plenty of fans, portable air conditioning units and cold drinking water is available to reduce the heat in offices, factories, shops, hospitals, schools and other workplaces across the country."
The motion comes as MPs finish for their 45-day summer break. It is unlikely to become law.
