The annual ban on outdoor work for construction labourers and others will begin on Wednesday, the government said.
Employers cannot require builders, construction staff and others to work in the sun between 12.30pm and 3pm.
The policy will be in effect until September 15.
Temperatures have risen in recent weeks and in July and August can reach 50°C.
Exceptions are allowed where technical work that cannot be halted is carried out, such as the pouring of concrete. This task is often performed overnight in high summer.
Mohsen Al Nassi, acting undersecretary for inspections at the Ministry of Human Resources and Emiratisation, said employers who do not allow their staff a break should be reported.
The phone number to do this is 600 590000.
"The employer must provide cold drinking water, commensurate with the number of workers ... and materials such as salt, lemon and others that are approved for use by local authorities," state to news agency Wam reported.
A daily work schedule in Arabic and other languages must also be placed on noticeboards so workers understand the timings.
Companies that break the rules face fines of Dh5,000 ($1,360) per worker, or up to a maximum of Dh50,000. Depending on the severity of the breach, the company could also have its status downgraded by the ministry.