At least half of Iran's 31 provinces will see public offices either shut or operating on reduced hours, the official IRNA news agency said.

Provinces affected include West Azerbaijan and Ardabil in the northwest, Hormozgan in the south, and Alborz in the north, as well as the capital Tehran.

Tehran governor Mohammad Sadegh Motamedian said the closures came at the request of the energy ministry and were intended to "manage energy consumption in the water and electricity sectors", state television said.

Emergency and frontline services will remain open, it added.

Elevated temperatures that began in mid-July have strained Iran's power grid, prompting rolling blackouts nationwide as temperatures in parts of Khuzestan province in the southwest reached 52C over the past 24 hours.

According to the meteorological office, the hot weather will persist across most of Iran for the next five days.

Authorities in Tehran have also reduced mains water pressure to manage falling reservoir levels, as the country endures what Iranian media have described as the worst drought in a century.

The frequent power outages have severely affected industrial output.

Reformist newspaper Shargh reported that factories were now facing four days a week of power cuts, compounding pressure from crippling Western sanctions and soaring inflation.

The outages have reduced output to levels last seen in 2020, at the height of the Covid-19 pandemic, figures from the industrial and mining sectors showed.