Tropical Storm Greg has been upgraded to Hurricane status as it sweeps along Mexico's western coast.

Nine people have been killed in flooding over the past two days as the storm pounded the Mexican Pacific coast with heavy rain and winds.

Officials have forced more than one thousand people out of low-lying areas.

Roads are washed out and homes flooded, leaving thousands more with no place to live.

"Greg's" centre is about 135 kilometres southeast of the resort town of Cabo San Lucas on the southern tip of Baja California.

The United States National Hurricane Centre says Greg is moving at a speed of 10 kilometres per hour and has sustained winds near 120 kilometres per hour.