More than 2,500 people were evacuated and a fishing village severely flooded as Hurricane Norbert swirled off Mexico's Pacific coast on Saturday, officials said.

The storm had surged to a category three hurricane on the Saffir-Simpson scale but by late Saturday had lost some of its punch and was a category two system, said the US National Weather Service, packing top sustained winds of 100 miles per hour (155 km/h).

Additional weakening was expected in the next 48 hours, forecasters said.

But heavy rains throughout the region were still expected, with the central and northern regions of the Baja peninsula bearing the brunt.

Around 2,500 people had flocked to evacuation shelters in Mexico after the storm lashed coastal communities, said Comondu mayor Venustiano Perez.

One of the worst-hit towns was San Carlos, a fishing village of 7,000 people, which suffered severe flooding after levees protecting the community broke.

"In some areas of San Carlos the water was one meter (three feet) high," said Pedro Garza of the Municipal Civil Protection Unit.

About 500 homes were damaged while some families who refused to leave their properties were forcibly evacuated, he added.

Last year, Mexico was simultaneously struck by a pair of hurricanes, Ingrid and Manuel, on both coasts, killing 157 people, destroying bridges and burying most of a mountain village in the Pacific coast state of Guerrero.