Members of the public take photos at the seafront ahead of the arrival of cyclone Belal
AFP

Hundreds of thousands of people on France's Indian Ocean island of Reunion hunkered down in their homes under a strict lockdown on Monday as a devastating storm that has already left one dead started to rip through the territory.

Cyclone Belal hit Reunion, one of France's overseas territories that span the globe from the Caribbean to the Pacific, moving in from the northwest packing "extreme winds", according to Meteo-France.

"The eye of the storm is passing over the Reunion Island, starting from the northern part," the meteorological service said in its latest public bulletin. It had previously said that Belal is not, however, expected to become an intense tropical cyclone.

"We're into the hard part," prefect Jerome Filippini, the island's top Paris-appointed official, told France Inter. "We will have a difficult and dangerous Monday".

While initial damage was still moderate "one homeless person who had not taken shelter" died as a result of the storm in the western settlement of Saint Gilles, the prefecture said.

In preparation for gusty winds that could exceed 250 kilometres per hour (155 miles per hour) in the highlands, authorities hoisted the violet-level alert, indicating imminent danger, at 6:00 am (0200 GMT), putting all 870,000 inhabitants, including the emergency services, on strict lockdown.

"All circulation is formally prohibited for any reason whatsoever, and until further notice," the official statement said. Even security forces have been prohibited from moving.

Reunion, known as La Reunion in French, is located east of Madagascar and has a population of almost 900,000.

Authorities urged islanders to stock up on food and water and stay indoors for 36 hours. They were told not to leave home "for any reason", unplug all devices, not use tap water and only use the telephone for an emergency.

Expecting waves up to 13-15 metres (43-49 feet) high, the entire coastline was put on alert.

Many balconies and gardens had been cleared of any objects that could be carried away or broken, and shopkeepers took in removable signs.

"We are not going to play heroes, we were told to stay at home," Jules Dafreville, who lives in the capital Saint-Denis, said on Sunday.

"I returned in the middle of the afternoon and I don't plan to come out before... Tuesday morning."

The island's main airport said it was suspending flight operations.

French President Emmanuel Macron took to social media on Sunday to urge residents to stay indoors.

"Be careful, stay at home," he said on X, formerly Twitter.

The last major cyclone to hit Reunion was in 2014.

But speaking about the dangers of the current storm, authorities evoked Cyclone Firinga in 1989, which destroyed hundreds of homes and dumped record-breaking rain.

Meteo-France warned of a possible "lull" as the eye of the storm tracked over the island, but added, "this should not be understood as the end of the cyclone".

"Quite the opposite, as the winds will pick up again in completely different directions," said Celine Jauffret at the forecasting service.

The weather service warned that winds could exceed 200 km/h on the coast and 250 km/h or more in the highlands.

"These are destructive and devastating winds that could cause major damage," said Sebastien Langlade, head of forecasting at Meteo-France Reunion.

Residents were also warned to beware potentially flooded rivers.

Six emergency health centres were set up for people requiring treatment, in addition to the 142 accommodation centres across the country for people to use in the event of flooding.

Olivier Blondet, manager of two restaurants and a nightclub in Saint-Denis, prepared his three establishments for the worst.

He fixed the sofa on his terrace to the railings and removed blunt objects, he said.

"We're trying to make sure there's absolutely nothing that can come off the ground and be thrown onto the windows or walls," he said on BFMTV.

In Saint-Denis, around 20 homeless people were taken to a shelter.