The "event of electrical origin" at the Ouroveni plant overnight from Monday to Tuesday "is leading to water cuts mostly located in the centre and south" of Mayotte's main island Grande Terre, the prefecture said.

Around half of Mayotte's population of 320,000 depends on Ouroveni's daily output of up to 20,000 cubic metres (700,000 cubic feet) of drinking water.

The island territory has for years been battling water shortages.

Low rainfall and numerous leaks in the distribution system prompted authorities to cut water supplies for as much as two out of every three days between August 2023 and January this year.

Cuts are still in force for one in every three days as "daily consumption is estimated at 45,000 cubic metres, but the territory can only produce a maximum of 40,000," said Jerome Josserand, head of the territory's DEALM environment, planning, housing and maritime authority.

Several schools -- usually continuously supplied with water -- were forced to send pupils home on Tuesday, with the education authority counting three middle schools and two high schools.

Mayotte's SMAE water company was "working to evaluate the consequences of the incident and the time it will take to get back to normal," the prefecture said.

In the meantime, potable water tanks have been set up in affected municipalities, the company said.