Floods caused by days of non-stop rain in southwest France forced the closing of most of the Catholic sanctuary of Lourdes Saturday and the evacuation of more than 450 pilgrims, local authorities said.

Buses ferried guests from all the hotels in the lower town to a conference centre and a sports complex as officials said the sites visited by millions annually would stay closed for several days.

Two campsites were also evacuated and several roads closed around Lourdes, where Catholics believe the Virgin Mary appeared to peasant girl Bernadette Soubirous in a grotto in 1858, as the river Gave de Pau burst its banks.

The water was around one metre (three feet) deep in front of the grotto and 80 centimetres in the avenue du Paradis, where most of the hotels for pilgrims are located, after what officials said was the worst flooding in 25 years.

Only the massive basilica, built on higher ground, was still accessible.

"The space in front of the grotto is entirely covered with water, the altar is under water," Thierry Castillo, the custodian of the sanctuaries, told AFP.

"There are torrents of mud," he said, predicting major damage which would be costly to repair.

Castillo singled out the hydroelectric plant which provides power to the sanctuaries, which was badly damaged by floating tree trunks.

The Gave de Pau was three metres (10 feet) above its usual level Saturday morning and still rising, as weather forecasters predicted that the rain that has been falling non-stop since Thursday would continue until Sunday.

A heavy downpour is forecast for Saturday evening and night.

"I've seen nothing like it in 40 years," said hotel-owner Pierre Barrere as he watched the pilgrims being evacuated.

Catherine Brun from Grenoble in southeast France was told to leave at 8:30 a.m. (0630 GMT). She said she had just had time to take her car from the garage before the water suddenly rose.

Rescuers evacuated her mother, who is frail, in a boat some hours later. The two women were taken to another hotel.

At a shelter for the evacuees, Kiki Klint from the Netherlands, who was accompanying a group of Dutch teenagers to the shrine, expressed her disappointment.

"I wanted to show the young people the statue of the Virgin, the processions and they won't be able to see anything," she said, adding that it was "terrible to see" the rising water which they had to walk through to get out of the hotel.

Lourdes attracted more than six million visitors last year. The Catholic church recognises 68 miracles linked to it and many disabled or sick people go there to pray for a cure.

The sanctuaries are not expected to reopen before Tuesday or Wednesday.