Insured losses from a devastating tornado that struck the US city of Atlanta, Georgia, and subsequent storms in other parts of the state on March 14-15 have risen to US$250 million ($272 million), with higher figures expected.

Georgia Insurance and Safety Fire Commissioner John Oxendine says the storm caused the largest loss yet recorded in the state for tornado damage.

Most of the financial loss came from downtown Atlanta, with landmarks including the Georgia Dome and World Congress Centre damaged.

The full extent of damage to property has yet to be determined.