Egypt's government has extended daily power cuts to three hours on Sunday and Monday, one hour longer than usual, in response to a surge in domestic electricity consumption because of a heatwave, a cabinet statement said.

Since July last year, load shedding linked to falling gas production, rising demand and a shortage of foreign currency has led to scheduled two-hour daily power cuts in most areas.

Earlier this month, a shortage of gas supplies led to temporary shutdowns at fertiliser and chemical plants.

The blackouts, which began last summer as demand for air conditioning rose, have stirred frustration among citizens and interruptions for businesses, and led to several reported deaths.

In one case, a saxophonist called Mohammed Ali Nasr fell to his death earlier this month in an elevator shaft in the coastal city of Alexandria, after being trapped in the elevator during a power cut, his brother told a local TV show.

Restoring and boosting power supplies was touted as one of Egyptian President Abdel Fattah al-Sisi's achievements in the years after he led the ouster of the Muslim Brotherhood's Mohamed Mursi in 2013.

Officials have blamed power cuts on rising demand from a growing population of 106 million and development projects.

Since the power cuts started, some Egyptians have been re-sharing or commenting critically on official posts from previous years about improved power supplies. Some of the posts were subsequently deleted.