One person died and another was missing as flooding inundated central Indiana, forcing evacuations and numerous boat rescues, a state official said.

"We have one confirmed casualty," John Erikson, spokesman for the midwestern state's Department of Homeland Security told AFP, saying he did not have more details about the victim.

He also said one person was missing as flood waters swamped areas south and west of Indianapolis on Saturday.

A nursing home and hospital were evacuated as rescuers used boats and helicopters to reach those stranded by the high water, according to Erikson.

The flooding in low-lying areas came after a torrential downpour on Saturday, with water rushing over major roads, closing parts of Interstate 70 and Interstate 65, and surging over a dam in Johnson County, the Indianapolis Star reported.

Governor Mitch Daniels issued a disaster declaration for 41 counties on Friday and for another 18 on Saturday.

"Mother Nature has landed another one on our chin," Daniels told reporters earlier.

About 530 National Guard troops were deployed to help state police and rescue workers with evacuations, searches, sandbagging and traffic control, the Star reported, quoting a state police spokesman.

About 1,230 people had taken shelter overnight due to the flooding and a lull in the rain had helped rescue efforts, Erikson said.

"We've been very successful with boat rescues," he said.

Sandbagging was underway in threatened towns as authorities braced for more possible flooding.

"We're expecting some rain later in the week, but we're not sure how much it's going to be," Erikson said. "We are preparing for whatever comes our way."