The US city of New Orleans, which is predominantly African American, has elected its first white mayor in 32 years.

Lieutenant Governor Mitch Landrieu, a Democrat, was chosen to succeed Ray Nagin, the outgoing mayor who could not run for re-election because of his term limits. 

Landrieu won the elections with 66.5 per cent of the vote as his closest competitor Troy Henry, a black Democrat with extensive corporate experience, finished with only 12.8 per cent in Saturday's vote.

"The people of New Orleans did a very extraordinary thing...striking a blow for unity," Landrieu said after his opponent conceded defeat.

Rekindled hope

Landrieu has become the city's first white mayor since his father Moon Landrieu left the position in 1978.

His appointment ushers in hopes of a new era in a city still struggling to rebuild five years after Hurricane Katrina struck.

"Everybody feels like they have to have hope," Ralph Ampey, a local, said of the election. "Whatever they lost in the storm -- homes, furniture, property -- they hope they can get again."

The new mayor must manage billions of dollars in federal reconstruction aid and a depleted city treasury.

Moreover, city hall and the police department are rife with scandals.

According to the state treasurer, violence remains high, which is repelling potential investors from the city that has a lot more rebuilding to do.